(I'm really saying the same as some other people have, but being a bit more tediously systematic about it.)
Options:
1. Keep using the lens. You have: MF-only lens, no change in money. 2. Buy another one. You have: MF-only lens, AF-capable lens, X less money. 3. Get it fixed. You have: AF-capable lens, Y less money. 4. Sell it. You have: no lens, Z more money. 5. Get it fixed and then sell it. You have: no lens, W-Y more money.
So, the key questions are (1) what are W,X,Y,Z? and (2) what's the value to you of (a) the lens without AF, (b) the lens with AF, and (c) the lens with AF and a backup without AF?
It seems like X is probably about £400. You're in the process of finding out what Y is. Presumably W is slightly less than X. Z is probably quite small and I'd guess that W-Y is bigger. As for question 2, only you can answer it, though if your finances haven't changed much it's reasonable to guess that the answer to (b) is somewhat more than £400.
After that, it's just arithmetic :-). Questions like "how does my total expenditure compare with having bought it new?" and "is this more or less than half what I originally paid?" seem entirely irrelevant, except in so far as they help determine your psychological state after making whatever decision you do.
no subject
Options:
1. Keep using the lens. You have: MF-only lens, no change in money.
2. Buy another one. You have: MF-only lens, AF-capable lens, X less money.
3. Get it fixed. You have: AF-capable lens, Y less money.
4. Sell it. You have: no lens, Z more money.
5. Get it fixed and then sell it. You have: no lens, W-Y more money.
So, the key questions are (1) what are W,X,Y,Z? and (2) what's the value to you of (a) the lens without AF, (b) the lens with AF, and (c) the lens with AF and a backup without AF?
It seems like X is probably about £400. You're in the process of finding out what Y is. Presumably W is slightly less than X. Z is probably quite small and I'd guess that W-Y is bigger. As for question 2, only you can answer it, though if your finances haven't changed much it's reasonable to guess that the answer to (b) is somewhat more than £400.
After that, it's just arithmetic :-). Questions like "how does my total expenditure compare with having bought it new?" and "is this more or less than half what I originally paid?" seem entirely irrelevant, except in so far as they help determine your psychological state after making whatever decision you do.