Simplest way is to use Paypal.
Set up an account with Paypal, and then you can use paypal url's to create payment buttons or items
Paypal lets them pay with either a paypal account or any credit/debit
gets you a years membership to the Gloucester Old Spot pig Breeders Club - feel free to click it, it takes you to a payment screen which you'd need to complete to actually pay !
code behind it is
<a href="https://www.paypal.com/cgi-bin/webscr?cmd=_xclick&business=mail%40oldspots%2eorg%2euk&item_name=Individual%20Membership%20email%20Newsletter&amount=15%2e00&no_shipping=1¤cy_code=GBP">Pay here</a>
The "business" is the username of the one you set up with paypal
The "item_name" is whatever you want to appear to the customer (and you once they've paid!)
The "amount" is whatever you want them to pay
You can then amend shipping and currency
Basically create a paypal account, then just amend the code above - simple
When someone pays you get an email from paypal giving the customers name, address and email address. You can always then email for any other info you want.
I use cformsII to create a membership form which integrates into paypal, but it takes a bit of understanding
visit http://www.rewweb.co.uk/club-membership-forms-using-paypal/ for a long detailed explanation of how to do this if you want to go down that route