See if your local area has a gardening club. Most areas that have allotments will also have gardening clubs, barring that, try local school fairs for garden bargains, ebay is a good place to find tools (be wary of buying used, they could be nicked from someone's shed), and I have had some seed bargains from ebay (60 assorted packets for around £12, some out of date, but if the packet is unopened, most will normally still germinate).
What you need to look for are perennials - these come up and flower every year, some are where the plant itself survives the winter, others are where the plant self-seeds, so will come up again next year. If you're not sure, google the plant name, that's saved me some expensive mistakes! Things that grow from bulbs or corms will normally come up every year, make sure you give them a good feed at least once a week (twice is better), and when you plant bulbs or corms, put a bit of grit or sharp sand around them, this helps keeps slugs away, as slugs will quite happily munch bulbs if they can get to them. Hope this helps.