UPDATE 1.2 (likely to be final)
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Finally i have come back and finished this mod!
This version now includes:
- added Chaos Damage from the Dragonborn DLC so all enchantments from the base Legendary edition are now covered (thanks to ismael29h for noticing i had missed this)
- included a plugin without Chaos damage for those without the Dragonborn DLC
- included a resource plugin with just the magic effects which can be added to the base enchantments to fix them
- this should allow people to add the fix if they have mods which change the base enchantments and don't want this overwriting those changes
- the corrected typo from Magica to Magicka for Fortify Restoration & Magica Regen which is included in the Unofficial Skyrim Legendary Edition Patch
- the patch is not needed for this fix to work, but now this fix doesn't undo that typo fix (thanks to EnderBlazer for noticing i had missed this out)
- and i would recommend the patch to everyone who has all the DLC because it fixes so many bugs

So as mentioned above, all the base enchantments from the vanilla game are now covered, and once the items are enchanted they will have a sensible, engine calculated value which will not change, and items will not be worth less as skill increases.
It should be noted that item value seems to be calculated based only on enchantment strength and the size of the soul gem, not number of charges. Higher skill levels and perks allow for greater strengths of enchantment which increases the value, or for more charges at a lower level which will have the same value as any other item of the same type and power.
e.g. enchant an iron dagger with turn undead with a lesser soul gem at enchanting level 15 and get 5 charges to turn up to level 10 undead, with a dagger value of 306. At enchanting level 100 enchant an iron dagger with turn undead with a lesser soul gem and get 16 charges to turn up to level 10 undead, with the same 306 gold value, or get 13 charges to turn up to level 12 undead, with a 358 gold value. Enchanter level 1 increases the charges to 21 for the turn up to level 10 dagger (still 306 gold), or allows 13 charges to turn up to level 15 undead, with a 438 gold value. Etc.

Any questions please post a comment. The main plugin (with Chaos damage) should work fine on SSE, but to get a version with the shiny new Form Version 44 SSE files please go to Enchantment Value Fix SSE

Original description below..... (sorry for width weirdness, original text was formatted fixed width for my tiny screen, got HD now :-))

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Skyrim Enchantment Value Fix
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Description
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This mod fixes the bug in Skyrim where player enchanted items
have incorrect gold values.

It removes an exploit where players can make large sums of gold in the
early game from weakly enchanted items, as well as an annoyance in the later
game where to get the correct value the game must be saved, Skyrim must be quit
and restarted from the OS, and then all the items must be sold before re-entering
the enchantment interface (since it resets them back to the incorrect values).

NOTE: The Frost enchantment is the only vanilla enchantment which does not
suffer from the value bug. It is incorrectly shown in the enchanting interface
the same as all the others, but as soon as it is created it has the correct and
stable value. This was how I worked out how to fix it, and the method is
explained in a text file which accompanies the modding resource download.
Also in this article
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Features
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- This mod WILL cause all player enchanted items to have the correct value as
soon as they are created in the player's inventory and for all time after. The
value is auto calculated by the game based on the item's enchantment and soul
size, and will be correct and stable no matter how many times the game is
saved, loaded, cold restarted etc.

- This mod WILL NOT stop Skyrim from showing incorrect values in the enchanting
interface. This seems to be an engine bug and is present on PC and consoles.

- This mod IS ONLY concerned with the GOLD VALUE of the enchanted items, for
those players who use enchanting to make money, but would like the item values
to be correct so as to avoid exploits in the early game, and annoyance in the later
game.
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Installation
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Just copy the .esp into the Data folder. For information about load order please
see the next section on compatibility.
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Compatibility
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This mod changes the base enchantment definitions.

It may therefore conflict with any other mod which changes these items, either
overwriting their changes or being overwritten, depending on load order and what is changed.

A note on load order: If you have mods which affect base enchantments, so long as you place them
after Enchantment Value Fix, you should get all the features of those mods, only losing the fixed
values for the base enchantments changed by that mod, while retaining any which aren't touched.

Therefore, if you use any mod which changes the base enchantments (Creation
Kit ID starts with Ench and ends with Base), any of these enchantments which
still suffer from the value problem will need to be fixed by a patch mod. It is
possible for a mod to have fixed the issue if it has added conditional effects to
the base enchantments.

More detailed instructions on how this fix works are included in the
"how_it_works.txt" file included with the modding resource download so that anyone can apply the fix
to their game by patching any mods affecting base enchantments. Also in this article

This mod will not do as intended if used with the Enchantment
Reload Fix by egocarib, since that mod recalculates the item
values to match those shown in the enchantment interface.
However, if you are more interested in the soul drain of your enchanted
items rather than the gold value, look to that mod, since mine does nothing
to intentionally address that issue (if you find it does it accidentally then do let me know....)
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Thanks
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Thanks to Bethesda for Elder Scrolls 3, 4 and 5 (the ones i have played and loved), and for giving us PC owners the tools to mod the games.
Thanks to Arthmoor (and collaborators) for the essential Unofficial Skyrim Legendary Edition Patch, without which the Dragonborn's journey would be buggy and irritating! 
Thanks to ElminsterAU and all of the TES5Edit team, which made my recent update to this patch so much less painful than the original CK way.
Thanks to all the other modders who make these great games awesome.
And thanks to the Nexus team for providing us with this portal of awesomeness! :-)
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