All but one of my retreats have been in the UK so I know it’s not cheap, particularly since I don’t live there so the travel is in itself a major financial drain. Have you asked your parish priest? Maybe he could help you find something within your budget.
Many retreats are costly because you’re expected to reside on-site for the duration, which means they need to house and feed you. Perhaps there are retreats near you that you could commute to each day rather than sleeping on-site. Those should be more moderately priced.
And don’t feel bad about having to limit your expenditure for a retreat. We can only do what we can do.