You won't get a new Bold 9700 for £150, maybe a used one from the bay of E. 8250's are below £130 if you look around but they don't support 3G or HSDPA. The San Francisco is probably your best bet, it is good bang for buck payg phone. Plenty of modded ROMs around if that floats your boat and it is easily unlocked for all networks.
The HTC Wildfire is around £150 and will be better put together than a San Francisco but slightly smaller screen and resolution.
The HTC Wildfire is around £150 and will be better put together than a San Francisco but slightly smaller screen and resolution.
You can pick up a mint condition T-Mobile Motorola Defy for £150.
Hard to beat for the money - Hell its hard to beat in the £200 price bracket!