My use of acetone is rather minimal. I still have 200ml left in a 500ml tin - and it's been like that for the best part of a year, if not longer.
My (as in I source it, pay for it and transport it) IPA gets commandeered for any use around the house where it might be beneficial ... I've even been known to use some for cleaning the things for which I actually purchased the stuff.
Anyway, I had been looking at buying more. The price for a small quantity is just painful, so I was having the same argument about how big to go. It was either 2L from Altronics (who, from what I've been able to find, don't actually say what purity it is they sell) or 5L 100% from evilbay.
Decisions, decisions.