I would beg. Near the airport or a significant tourist hotel might work. Explain that any donation would be helpful. A sign that shows your $100 goal might prompt people to help.

A travel agency might take pity - the larger ones may have some clout to get fees waived.

I have given to tourist in need several times before. E.g. when the person in front of me overstayed her visa in Thailand and was out of money (fine was $10). She wouldn't be allowed to leave and miss her flight without it. I also gave a couple $25 when the ATMs and credit card processors went out of service in an entire town for 24 hours - to tie them over.