It could be as cheap as 20$, but you need to know what you're getting yourself into, since the guarantees might not be so high, like problem resolution time; in general, you would want to have the management from the provider, as it is often cheaper than outsourcing it.
High Bandwidth Servers
Custom Hosting Solutions
A managed VPS provider would definitely be cheaper than buying an unmanaed vps and looking for outsourced support. However, if you are dead set on an unmanaged provider, and you want cpanel/whm, check out Platinumservermanagement.