I paid $250 for my portwork at Patriot too. It's easier for someone to charge a cheaper price for port work that just isn't as labor intensive. A woods port to me wood be one of the easiest, these isn't a whole lot to be done, you just need the knowledge to do what needs to be done the right way. The MX port I had done on my RZ didn't cost as much because the port layout of RZ motors is SO much better than a Banshee's stock. A triple exhaust drag port I have seen go up to almost $1000. It's hard to put all port work in a basket based on just price alone.
Don't take any of that as a bash on Gore even in the slightest little bit. His work seems to be top notch. I have ridden with Spoin who I do believe had his work done by Gore and his bike rips(actually I think he knows him.)
Best of luck, a search on this subject probably would be almost useless, it has been discussed so many times it would take you days just to go through the results.