Personally, i like CubeCart - i run that on several stores, and CC3 has just been released which looks very promising (still in alpha stage, so still bugs yet, but V2 works quite well.).
Most hosts will offer an auto-installer for OSC - LSC Web Hosting (Myself) offers a Fantastico installer for OSC, CubeCart and ZenCart which means that your shop is up and running within 5 minutes.
My paid plans start at $3/mth for 200MB space / 2GB Bandwidth, which is more than enough to get started. Feel free to email me if you have any questions:
hosting@lightspeed.net.au