I have used this method for buying machines and would do the same if I ever sell one.

As far as mods/parts purchases, PayPal "goods" works best overall. As a seller I find that it gives the buyer assurances that the transaction will go well. It also makes it easy for me to ship using the built in shipping tools in PayPal; simply print label and stick in mail box. The fee is much less than my time is worth to go to the post office. When a seller wants PayPal "gift" for payment, as a buyer it makes me wonder about the transaction.