If you're doing an offer, there are a lot of offers out there, but there are few that I recommend to make your experience quick and easy. If you're going to trade referrals for registering as completed on the offers page, skip to the bottom.
UK Offers
The first of these is the Coral bookmakers offer. Similar to the Gala Bingo offer, you deposit £5 and play it through, and it will register as completed, usually within 30 minutes. However, with the coral offer, not only will it count as completing an offer, but if you place your bets right you're actually guaranteed to make money out of it. When doing the Coral offer though freebiejeebies, if you deposit £5 or £10, they double the amount in your account. You can use this to your advantage, by betting half the amount in your account on one outcome of a tennis or cricket match, and half of it on the other outcome. No matter what happens, you'll end up winning more than you deposited, and it also counts as completing an offer. It really is win-win, it's almost like you're being paid to get a free gadget!
Another good offer is the LoveFilm offer, they have a 14 day free trial, during which you rent one DVD for free, and that counts as the completion of your offer. Just send it back using their free envelope within the two weeks so you get to watch a dvd for free, and you're well on your way to getting that free PS3, iPod (or in one custom order I saw recently, a free shed). 
Another one of the offers I recommend is the Gala Bingo offer. All you have to do is register and deposit £5. Once you've played it through (made £5 worth of bets/wagers) then the offer registers as completed (usually within 30 minutes). So not only do you get your free PS3/iPod e.t.c. from the referral site, but you have a pretty good chance of winning some cash. I've heard of several people at eXceem winning between £50 and £100 just from betting their £5 deposit.
US Offers
If you're in the US, the offers are slightly different. The equivilent of the LoveFilm offer is one from Blockbuster. Again, you'll notice this is a very respectable and trustworthy company. This does, however, cost $9.99 to complete the offer, but let's be honest, getting an iPod or PS3 for $9.99 isn't exactly expensive, and you get a full month of free rentals.
Another good offer is from Credit Check Total. If you're feeling the credit crunch, they offer 3 free credit reports, and that counts as you completing the offer. It's also a very quick offer to register as completed, so you can start getting your referrals for your free PS3 right away.
Before completing an offer make sure you read the 'Hints and Tips' section, to make sure freebiejeebies tracks you completing the offer. It's only a couple of quick and easy precausions to make sure you get your free gift!
Getting a free gift without completing an offer
Because freebiejeebies is one of the better networks around, they accomodate for people who don't have credit or debit cards. By getting 3 extra referrals, you can get your free gift without completing an offer.
To do this, once you have 3 referrals go to the support page. Start a new ticket, and file it under general enquiries, low priority. Then simply ask to trade 3 referrals for registering as if you completed an offer. Given freebiejeebies' excellent customer service, they should have updated your account within the hour.