Via this offer on WHT, xenSmart has 20% recurring discount on their Xen VPS, which makes the cheapest plan at £4/month (that’s around USD$6.55/month). Use coupon code FILLEM to get the discount, and it’s for new customers only. You get:
128MB memory/128MB swap
10GB storage
150GB/month data transfer
HyperVM
Server at UK at BlueSquare. Currently it says “**ALL VPS [...]