Would advise against it unless you have one since you're concerned about costs.

You just need to research properly. From what I understand, you have a year? So make the best of it. If you're serious, apply for a scholarship. Costs are (sadly, but should not be, in an ideal world) prohibitive in making choices about education.

If you got into LSE by merit, there are plenty of scholarships that you should look into. Just research. Plenty of the LSE student body are scholars.