It's not quite as simple as rich colleges attracting applicants who would genuinely benefit from more money, and rich applicants picking poorer colleges out of benevolence to allow other people in more need to get at the richer ones! That would be a nice system. But when you say 'financial problems', what do you mean? At all colleges you are going to have to pay your tuition fees at international rates, your accommodation and food bill, and the college fee. If you won't be able to pay these, there isn't going to be a college that will help you; significant help is only really available for British residents. Anything else will just be small grants (a few hundred pounds for travel, the college paying for your music lessons, etc).
Accommodation fees in each college will vary from as low as £60 per week up to around £110 per week. Generally richer colleges will have cheaper accommodation, as they can afford to subsidise it. For specific details, contact colleges you are interested in.
Beauty is, of course, entirely subjective. Trinity and John's have lots of land, so plenty of trees and flowers there. Most colleges have nice gardens, though. Emma isn't huge, but I can see a lovely blossoming tree out of my window right now (or I wouldn't be able to, if it weren't dark). If it's impractical for you to visit, try looking at the college websites? Most will have photo galleries. Start at www.cam.ac.uk
, go to colleges, and there'll be a description of each, which should link to the college's official website. Then you can see what kind of trees each college has to offer!