it ain't ebay but it ain't rocket science either, lets get started:
1 PICK A SELLER
Go with a solid reputation: high rating, lots of good reviews, good delivery times. New sellers can have great deals but it's best to try them after you have some experience with bitcoin and little biggy. You want everything to go as smoothly as possible.
Though you can buy without an account its always better to register on little biggy, since a made up username doesn't identify you anymore than no username it's only got upside. If anything goes wrong follow up is much easier to deal with if you have an account and you are building reputation which is important for buyers as well as sellers.
At it's core little biggy is a reputation system everything from visibility, and, feature availability and dispute settlement relies on it.
you're going to need some bitcoins instructions appear below. note that item's prices appear in green if usd/cards are accepted.
once you've selected your item press BUY (duh).
enter your correct name and shipping address (deliveries can fail without this) and hit PAY. you will be transferred to a payment processor site where you get either a credit card form or a bitcoin address to send your payment.
if you are using bitcoins open another tab/app to access your wallet and send the coins to the stated btc address. within a few seconds (credit card) or minutes (bitcoin) your payment will be received and you will be forwarded back to the little biggy "order page". if for some reason this doesn't happen don't worry, both forms of payment have receipts built into them, just let your seller know what happened and you'll get sorted out.
3 order confirmation
if you've registered there's nothing to do here, within 24 hours (sunday- thursday) your order status should change from "paid" to "shipped", if not send the seller a message right there from the order page. though you can press "request refund" while your order is in "paid" status its best to do so only immediately after the order (if you made an error) or after a delay of 2 or 3 days, otherwise you may be tripping over the seller's shipping process.
if you have purchased anonymously your first look at the order page is very important. make sure you save the order url and password, there is no way anyone can retrieve it and the page tends to time out if you blow it off until later.
4 leave feedback
after your purchase you'll see a red number next to "ORDERS" return reminding you to go to that page to leave feedback, do so as this is what keeps things humming.
always contact your seller first. however if your shipment hasn't arrived within 2 weeks and you are not satisfied with your seller's response to the situation you should hit the REQUEST REFUND button. although a decent seller will give you time to work things out the escrow providers here tend to operate in 2 week cycles. once you change your order status to "refund requested" you should be hearing from your seller since he can't get paid; regardless the escrow provider will communicate with you to resolve the matter. again it's helpful to be a registered user since your buyer reputation is a factor (along with others like the seller's reputation, recent activities and the existence of shipment tracking).
if your problem is quality rather than shipment it is again best to work it out with the seller. if you are a registered user you can leave feedback and that's important to your seller especially if there is a consistent problem happening being reflected by more than 1 user. if you still get nowhere you can REQUEST REFUND and the escrow provider will be inclined to return a portion of your payment if there is objective corroboration like other complaints or seller unresponsiveness.
always keep biggy's positive vibe in mind. hijacking threads and rude posts don't earn respect here and are bound to cost you. if you need to vent always give people the benefit of the doubt and show that your words are sincere and unselfish, you'll quickly make friends and earn respect that helps you.
happy buying! if you need anymore help just use the topics threads on this page.