I'm not part of the Jasper community, instead the Banff/Canmore end of things. Yes the park rules changes the prices, but that's the fact of working in the national park system. Banff is atrociously priced, hands down. I'd imagine Jasper is similar. All I could recommend is looking into the town of Hinton, which is about as close as you get to being in the park, at non-park prices. It's a small, blue collar town which you'd find as more realisitc prices and people (family atmostphere, etc). If you can stomach the commute (just under an hour, might work depending on the job) it could help.
Jasper, like banff has many transients. Many young people from Australia, New Zealand, Britain, etc. on holiday work permits who attend to the tourism industry. The town itself is relatively very small, intimate. I can't speak to the locals who are permanent, long term, but if it's like the long terms in Banff, it's a tight nit group.
Either way, you'll find a difference in the community outside of the main tourist season (Victoria day to Labour day) but price wise (groceries, for example) won't change, unfortunately. An expensive, but breathtakingly beautiful place to live.