The cheapest flight "item" I can think of is the Feathered Wings graft from Fiend Folio, which costs 10,000 gp. However, the crafting feat requires 10 ranks in Heal, so you probably can't get it for a few levels.

Really though, I don't see why you absolutely need long-term flight at level 5. Overland Flight is likely not possible at this level while Airstep Sandals isn't very hard to catch up with. Get a wand or eternal wand of Fly to UMD and you should be fine. I can't imagine needing more flight than that at such a low level.