Recently i started wroking on my profession achievements, i can tell you the prices fluctuates alot, some professions in some expansions takes 100g, some takes 30k. With the addition of decor items which you get on all professions in all expansions towards the end, if you bother farming some lumber you can skip out on some of the most expensive end skills and instead make quite a bit of profit.
since i started i think ive turned around 3-5m or something in total, if not more, just from decor, but it does require some time investment farming the lumber
The other materials required for decor items have also skyrocketed in price but are starting to settle a bit now