Page kits are really cheap at between $4-7 usually, and you can reuse and alter all the stuff. Definitely cheaper!
Pro printing is usually cheaper than printing at home, though ink and printers and paper have gotten awfully cheap. I just save my layouts onto my photo card, pop it in at Sam's Club, and have archival prints while I shop
12x12 is cheaper to do at home, even after buying all the new equipment needed. Though even those are getting really cheap at some places now. Uploading to an online photo printer is easy: just create a large, high quality jpg copy of your layout and email it. They'll mail them to you.
Your regular supplies will still come in handy. YOu can do all sorts of digital/paper hybrid pages: no reason to limit yourself. Do in digital what you like, and do in paper what you like. There are strengths and weaknesses to each form. And don't forget invitations, cards, and other paper crafts like posters for church activities and computer crafts. I let my kids make art with my stuff now too that my oldest is capable. Not the expensive stuff, though!
Have fun, it's addicting!