My budget is below $30, I want low cost as possible as I run a small forum. Reliability and good customer service are priority. What's the difference between shared or VPS (and managed/unmanaged)? I prefer the UK.
A VPS is your own virtual private server where you effectively get your own disk space, services etc and they are yours. Shared hosting you share services etc with others on the server. On VPS you can also install other software such as Imagemagick (used for converting images and videos - some parts of XenForo Media Gallery use this) whilst on some shared hosting you can't have it installed (as you're sharing with everyone else). Shared hosting can also be oversold and you can have other users hogging the resources on a server. It's probably best that you Google about both and find out more.
If you do go for VPS, you'd also need to decide on whether you go for a managed (the host does much of the work for you) or unmanaged (you do pretty much everything yourself).