In my low income multifamily projects I've used two different systems with decent results:
The first is PayNearMe. My tenants can walk into any Ace Cash Store or 7-Eleven Store in the nation and pay what they think is a money order. It costs them $3.95, but they can pay their rent or anything else with cash on hand. This works well for tenants that don't have bank accounts. Within a few minutes of them paying, I get an email saying when / where / how much they paid... and two days later the money is direct deposited into my business checking account. See www.paynearme.com for more details.
The second is online payment via property management software. I use Buildium, though there are several others like Appfolio, RentManager, etc. I've not used any of these but Buildium, but I really like this second method because the ACH or CC transaction costs can be charged to the tenant, and their payments are automatically entered for me into the accounting part of Buildium. The tenant portal website is simple enough that tenants can access it on their phone, so this works for all but the most technically challenged. I literally do nothing other than wait until the day after the payment grace period to start contacting renters about non-payment. Buildium even automatically applies late payment charges for me, so there is very little to do with this method other than watch the rent roll in. For more info see www.buildium.com.
Today I use a combination of the two. For tenants that just don't have the online skills I still accept PayNearMe, but I only offer it as a payment solution if they just flat out can't access the only system. Even in those cases I'm starting to offer to login for them and affect payment with their debit card or money card number via the online system.
Hope this helps. There are lots of options out there, but with technology today I wouldn't even think of having a park dropbox or manager collecting rent.