Whether you are earning skill ups (from continuous combines) or paying to train in tradeskills, TS'ing is a plat sink. However, if you only need a certain amount for something, like a high enough Baking to make yourself some food, then an easy way to bypass skilling up like that is to wait until your level equals the trivial level of the item to buy the tradeskill from your GM. Newly bought skills start at whatever your level is when you buy it (that or +/- 1).
For example, one of my toons makes
Mammoth Sandwiches for all of my other toons. When he reached 31 (which is the trivial skill level required to not mess up the combine [that's what trivial is, right?]), he bought Baking and it started at a 31 (IIRC). I make these mainly because 1 Loaf of Bread plus 1 Mammoth Meat makes 5 Sandwiches.
Side Note: Your toon's level doesn't have to equal the level of the recipe trivial. Just realized that sounded kinda confusing.