1. Message the seller
2. Know what you're buying by asking questions and getting more pictures if necessary
3. Agree on a price
4. Pay via Paypal with a "For Goods/Services" transaction only
5. Provide your shipping address
The buying process on HopUp is very open. By that, we mean you and the seller decide how to commit the transaction. As of now, you can't buy something with a credit card on the spot on HopUp.
When you are ready to buy something, you should message the seller and agree on a price. He/she will then provide you with their Paypal information. You should only send a seller money via Paypal as a "For Goods/Services" transaction. This is the safest way to pay an individual for an item online. Include a brief description of the item being sold in the notes of the Paypal transaction.
Provide the seller with your shipping address and wait patiently!
If meeting in-person, do it in a safe, public place. Meeting a local airsoft store is best and highly recommended. Always keep airsoft guns in a gun-case and do not flash them in public.
Side note: Refreshing the shipping carrier's tracking page every 5 seconds doesn't change how fast you'll receive your item ;)