I'm interested in getting myself an iPhone 4 but going to be using my current sim so don't need to go down the contract route (my sim is contract)

I wanna get a 2nd hand one, but how do you tell the dodgy blocked ones on ebay to the decent ones? Is there certain things to look out for?

Help greatly appreciated

The main thing is that the iPhone 4 takes a micro sim, so if your current contract SIM is standard size, your provider will need to give you a micro one, or you'll have to cut it down yourself (but that has some risk involved).

the dodgy ones will probably say no charger no box

As someone who has just sold one on EBay I would look carefully at the sellers feedback. See what they have been selling, if it's an individual and they are always selling phones and the like it could be that they are knock off or fake. Always communicate with the seller and get a feel for them from what they say.

See if they are prepared to give you their number so you can ask questions about the IPhone before committing yourself. Always pay with payPal (never cash) it gives you another level of confidence although it's not a 100% guarentee..

Just be wary, if at any part of the auction you feel uncomfortable, pull out of the sale. There will always be another IPhone just around the corner.

Bottom line..................common sense!

I often think that if you cannot afford it, consider something else.
With an often sought after item like the iPhone there will be many many 'temperamental' carousel phones getting passed around.

I've bought loads of refurbished and used laptops and stuff no problems whatsoever, mainly because its more a buyers market.