Lets look through a couple professions by level:
Chef: 19-90% profit possible by from chef level 0 to 100. 49% profit at level 100, but you need a steep karma input, or a near 0 profit for a minimal karma input. 125-149 gets you 29% profit, but at 150-174 there’s no profit to be had – I suggest karma recipes. 175-199 has profit, 200-299 is all profitable, but you may need to outlay some karma, 300-325, just aim for the cheapest thing to make (peach cookies), and after that the range of profitable recipes opens up.
Tailor: Profitable at all levels, although a couple have very few choices for where to make guild wars 2 gold.
Leatherworker:I’ll let you decide (see image). I’ve listed just the masks and helms, aiming to get a cross-section. Rows in bold you can sell to the high bidder and instantly make a profit. Non-bold rows you may find yourself waiting a few days or occasionally weeks to sell, but that’s the nature of any market where prices shift.
The money’s there, and if you choose wisely and price properly, things will sell. The level 80 stuff is currently a big risk however, with the announcement of ascended gear. Sub-80 stuff should sell, but again with the release of ascended gear, it looks like people will need to craft their own, meaning lots of them may craft stuff and dump it on the market at a loss in the weeks to come – In short, normally you can make a profit leveling up, but we’re at a sensitive stage where that may not hold true for a couple weeks.