The cheapest would be still images of the site, but the client may not like that.
If you are looking for a good hosting service, I would HIGHLY recommend
Host Gator.
You get unlimited diskspace, unlimited bandwidth, and a shared SSL certificate for $4.95 per month.
I usually keep my clients' sites on a particular section of my site that nobody else knows the domain to. Once they pay, I transfer the files to their account. The best part is, every time I sign up a client with Host Gator, I get $50 via paypal, so it acts as a small monthly income if you get enough clients.