"...a guy on a budget?..." Custom firearms and guys on budgets don't go together well.
However, Marstar is listing an M700 ADL barrel in .308 for $199. No mention of how long it is or its contour though. Likely a standard hunting barrel. A heavy barrel will cost more than that. If you can find one. Not many shooters buy a heavy barreled rifle for the action.
Too long can be cut and re-crowned. An SPS is an up graded ADL. Should be the same barrel, but I'm guessing at that.
Where you are in Southern Ontario matters. Epp's, for example, wants $150 plus the cost of the barrel, to install a barrel. Starts at $75 to cut and recrown a barrel.