Checking my alchemist privilege

A level 5 mage decides to hire himself out in downtime as a specialist alchemist, and earns 250 gp a month.  Cheap exploit, or reasonable given he's forgoing other uses of that time?

If no, does 1 or 2 ranks of Alchemy, but not 3, change the answer?

My personal ruling would be (not an Autarch):

A level 5 mage is not an alchemist; he can only create potions at the same rate, he can’t identify potions, potions, etc. Depending on your campaign world, nonmagical alchemical items may exist as well, which he cannot create.

I would allow 1 or 2 ranks of alchemy plus being a fifth level mage to hire out at a reduced rate, probably 100 gp/175 gp for 1/2 ranks.

Does he have Alchemy 3? If so than sure.

I agree. It's reasonable. He can't do everything an alchemist can do, but he can do some things an alchemist can't do. It's a totally reasonable wage for a non-adventuring mage.