If you're going with cPanel and in the $45/month range, you're in the right market for managed VPS hosting. Much cheaper than that and you have a pretty high risk of dealing with a company that is understaffed for the amount of tickets that they get.
There's definitely some providers out there in the $30/month range with decent disk space and bandwidth, but run a check with them on how many accounts they place on each node and how large the server is that you're going to be on. This will play into a factor of how much CPU power you get to utilize, and the same with memory. 512MB memory is a MINIMUM that I'd put any account on that's running cPanel. Ideally, 1GB+
cPanel will not work efficiently on a server with 256MB of memory (it MAY work, but you're asking for problems, especially after you put an account on there). If you can only get a small amount of memory, stick with DirectAdmin or LxAdmin.
Myself, I use VPS machines for some of our testing accounts or mini-accounts I'm setting up for clients and I won't even touch a VPS unless it has near 1GB memory (and more, depending on the scripts being used on the site).
More and more these days, PHP programs are requiring lots of memory to operate. Wordpress says it requires 32MB, but the reality is, once you add in plugins etc, it can often take up 128MB per processing instance. If you only have 256MB on the machine, you can really hinder basic performance, let alone once the site starts getting traffic (simultaneous visitors would slow down the machine, and enough of them would crash it).