Got to 46 and am flat broke, sold almost everything and still can't afford to upgrade some skills even though I have the spirit.

Still using my level 37 2 star axes because I can't afford to upgrade weapons or even armor.

Is melee in this game only possible if you can subsidize it with something like a venomancer?

No you just have to know how to make/manage money. I got a 50 BM with about 500k left and I've been upgrading my armor every 10 levels and upgrading my weapons less than that (I use different weapons). The skills do cost alot though, but I'd say melee classes waste all their money on having to buy those damn expensive health pots.

With a veno you can support any class though. Veno's are good farmers and you should be able to make like 200-600k every week farming with a veno.

I have kinda the opposite problem of yours. Only thing I have a problem with is trying to find a good weapon to spend my money on in the first place. Good melee weapons are scarce for lower levels.

 yeah, you need to farm more most likely. Also sometimes you have to limit skills to only the ones you need. don't do dragon quest too often it eats money away fast. you have to make choices at a lower level.