Just use your standard link building techniques: blog posts, signature line on forums, article marketing, directories, press release, etc.
PPC is the best way to lose money. You should only use PPC AFTER you have had some success with organic traffic and AFTER you have made some sales - to make sure your business model is sufficient. Majority of the aStores get abandoned after a couple of months of nonperformance anyway. Specialist websites do sell better. Write informative pages about your products.
I agree with all above. Another quick thing is to write articles and submit to the big ones like ezinearticles.com
Don't even think of using PPC if you are promoting books or any other low value items. If you are promoting high value items, then it may be worth trying. Effectively, one is likely to get in to loss if using PPC for low value items. Try to build content, advertise in relevant forums, etc. and rank high in search engines.