Cheapest Head unit with GPS?

I'm looking to buy a Head unit for my MR2 roadster.

It has to be double din, and it has to have USB and GPS whether it is displayed/mirrored from iPhone or built in.

Anyone got any suggestions on a good one for the lowest price which is available in the UK?

Don't cheap out here. I can't tell you how many times I have people come into my shop with the $100 double-din GPS head unit they bought off eBay. 50% of them have oversized faces and don't even fit in the dash kits for their vehicle (especially if the face flips down). 25% are defective right out of the box (had one today as a matter of fact), and the rest fail in under a year. Buy a quality name brand.

Secondly, any unit is going to be far cheaper if it doesn't have built in GPS. So if you're OK with having it mirror off your iPhone, that's going to save you a ton of money. Pioneer's newest App Radio 3 is pretty nice. The App Radio 1 and 2 were a little buggy, but they seem to have nailed it now. The screen is, literally, second to none. Gorgeous. And it comes in two flavors, with or without a DVD player. So if you can just play all your music/videos off your iPhone/iPod/USB/Bluetooth, save the $100 and get the cheaper one. Surely Pioneer products are available in the UK.