I am considering doing an MBA in the UK or US. But as I am on a budget I cannot afford an expensive program.

I am looking at MBAs like Loughborough, Brunel, Durham, Sheffield, and Nottingham. I have not shortlisted US programs yet but CSU Long Beach looks interesting to me.

But I am a little confused about the ROI. It is difficult to any information about the results after graduation for these MBA programs.

Can somebody advise about the ROI?

For the US, if you are on budget, Arizona State University - Carey and University of Florida - Hough are free... and better than all the ones you listed
For the UK, Durham is the only one in your list that can compare with them

RoI depends on many factors including whether you have permission to work in the country. Generally, it's better to focus on NPV rather than RoI.

I do not currently have authorization to work in either country. :(

It's much easier to get permission to work in the UK than in the US.

See https://find-mba.com/board/general-forum/best-schools-for-international-students-placement-35651

In general I agree that a UK program would probably be a better option if you want to work in the country you study in.

Durham is the only UK program that you're looking at which is ranked in the FT. In that ranking, it doesn't show that it has great international mobility - in fact, among UK programs, it's the second worst for international mobility after Leeds. You'd have more success if you were able to aim a bit higher - Edinburgh, Imperial, Warwick, etc.

UCD Smurfit is also an option, if Ireland is on your list