I would think should expect to spend anywhere from $7 to $20/mo for what you currently need. From the multitude of posts I have read over the past year and a half, it seems you can't go wrong with the following companies:
: Elite or Mercury plan.
: V20 or V50 plan.
: Basic or Advanced plan. (More expensive, but WELL worth it).
: Gold plan.
: Starter or Basic plan.
Be careful of HostWay and FutureQuest, as they both charge quite a bit for certain upgrades (HostWay with MySQL and FQ with subdomains I believe).
You'll get lots of other suggestions for newer, less experienced hosts, but these 5 seem to have the most staying power or any.