Bite the bullet and go farm the solvents yourself, with the "pure water" nodes it is quite fast. You should be good with about 40 each of the non-veteran solvents and about 300 of the V1 solvent.

Then check the guild stores for mushrooms like Violet Coprinus, White Cap, Stinkhorn and Imp Stool. Those are really cheap as they can't be used in good pots. Do two herb pots from these (check the possible combinations beforehand with e.g. Potion Maker addon or a web search).

Last time I powerleveled alchemy this way, it cost me less than 10k to get to 50, but I had some herbs on storage.