I sell on eBay, and I think I can answer a few of your questions, Crackers...
There is no sending the item until you get paid - eBay doesn't even prompt you to print a shipping label until the buyer pays. (You do have the option to go to the Post Office, but I think eBay gets you a USPS discount + a tracking number, which is useful).
If the buyer hasn't paid within 4 days of purchase, it automatically goes to an unpaid item status, and eBay - to the best of my knowledge - haunts the buyer until they pay. After x amount of days (I think it's 30), eBay will relist your item for you, and the buyer who 'defaulted' gets a strike on their record.
I have had two instances of this happening when I first started, and then I learned I can set buyer restrictions: if someone has had two unpaid item cases in the past twelve months, they can't bid on my stuff. I also don't allow anyone who doesn't have a Paypal account to bid, as I am not set up to take credit cards!
I probably don't get as many bidders this way - but the stuff that I do sell, I get paid for in a timely, stress-free manner. I price my items at the minimum that I am willing to take for the item (as opposed to just donating or giving it to a friend or family member). I usually get my minimum, not usually more than that. As Mo says, there are stretches of nothing selling, then I will have a bunch of stuff sell in a short span of days.