Guild Wars 2

So I have a level 50 Guardian, and I’m wanting to bump him up to 80 as quickly as possible through crafting. He’s already at 400 Jewel Crafting, but what I’m wondering is if there is a crafting skill in particular that will give him more experience. Through Jewel Crafting he went up about 10 levels. Will any other skills get him over 10 levels by maxing to 400?

And also, If I could get an estimate as to how much it might cost to get him from 50 to 80 through crafting. That would be great.

all of the crafts will give exp by leveling them up. chef is the cheapest.
the remaining 6, however, will only give 10 if you get them to level 500. and going from 400 to 500 costs around 100g each (while 1 to 400 costs about 8g)
so if you get the other 7 crafts to 400, you could get about 52 levels for about 50g. since you’re already level 50, you will only need to max 4 of them and then a tad bit more

The answer to this depends on whether or not you have been gathering material or not.