Yeah, I have a problem with incentives for paying on time--even a $20 gift card. I think the reverse is best. First, if you have a high number of resident email addresses, you can send an email before the 1st with a reminder. Then another on the 1st, and one only to lates on the 6th. Or you can do this with paper notices. One thing I've tried, and it was controversial, is that on the 6th I sent the late residents a note with names of local currency exchanges, payday loan places, etc., with addresses, contact info and phone numbers for them. Whether this embarrassed them or just provided guidance I don't know, but it helped.