By far the best place in Vancouver to buy new outdoor equipment is the member-owned Mountain Equipment Co-op [130 West Broadway.] Staff are extremely well-informed, prices are very fair and quality is excellent. Lifetime memberships cost a mere $5. Stores like the Army and Navy or 3 Vets [now closed] only sell outdoor trash that can cause real problems in the field. As a bonus, staff at the latter one used to yell at you if you walked into the store with a knapsack. No wonder they failed.
MEC also has a gigantic notice board for those interested in picking up their equipment second hand. Craigslist is another good bargain sources as well. For many newbies, the outdoor lifestyle becomes a consumer experience. They buy all the name brand gear, head out into the outback, despise it, then, after a hiatus of several years, sell off their equipment at garage sale prices. Look for these guys.
Renting is always a possibility but it does tend to be expensive, especially if you intend to take up the great outdoors as a lifestyle. Rental shops seem to find it difficult to survive in Vancouver. Until recently, about the only one that seemed able to make it in the local market is associated with the outdoor club at the University of British Columbia. Though inconveniently situated for most of us [6000 Student Union Boulevard, UBC; 604-822-1684] UBC Outdoor Equipment Rentals nonetheless has the goods if you need them.
In the last few years Mountain Equipment Co-op has stepped in to fill the rental gap on a more permanent basis.