Never have been easier, you only need to set up one action called: "Donation Button" to enable that players could donate to you using your map...
Of course you must have a PayPal account and you must know the Email address you use for it. Also its good if you check what currency you use as you will be able to set that too.
When somebody donates to you with it, you will able to see the map's name and the player's battle.net handle.
This the first Library I made so it might not be perfect and I only used gui.
Players will get links like this: https://email@example.com&item_number=Random+TD++2-S2-1-913984¤cy_code=EUR
Dont give me credit, give credit yourself:D
You can get the library from here: http://www.sc2mapster.com/assets/library-paypal-button/