You can use any language you're most comfortable with. Database, same. A popular choice is PHP/MySQL because of the price point (free).
If you're not a programmer then it's going to cost your some real $$$ to get the website developed.
Paypal's a fine choice, and popular, but it's not the only choice. Just google "payment gateway" and you'll see you have dozens of choices. Paypal has an advantage for starting websites without much revenue coming in because their "basic" plan does not charge a monthly fee (but the percentage is a bit steeper to compensate). If you choose to go exclusively with Paypal make sure your developer is an expert with Paypal's IPN system, because that's where you will update your database when a payment actually lands in your Paypal account.