The best way to collect application fee

[Dave Lin]

During my house showing, I find that most people prefer taking the application form back home to fill out. Usually, they can scan and email me the form in one or two days. However, I may have to meet an applicant again to collect $30 fee or give him/her my home address to mail a check.

What is the best way to collect such small fee with minimum effort? Any comment is highly appreciated.