I want to move to London with crappy grades help?

You have no chance of getting a scholarship - in the UK these are rare, worth relatively little, and given on academic merit.

You can get a student visa for the UK if you fill the following requirements:
- a confirmed university place (college in the UK is for 16-18 year olds, similar to high school)
- proof you can afford the FULL cost of studying and living in the UK (for London, you'd easily be looking at £30,000+ a year)

Even if you could get a student place,you'd be returning to the US on graduation (no post-study work visas), so you'd need to ensure whatever you studied would be recognised there.

You would have to prove that you have enough money in the bank to pay for your complete college course tuition, plus living expenses, before you could attend university as an international student in England. You would also need a student visa, and you can't work full time and attend university on a student visa.

It would be much wiser for you to complete your education in your home state (much cheaper), save your money, and move to London once you have a degree that will let you make a living wage in England.