I'm one of the early adopters, so it's not that expensive for me. Normal price is $24.95/year. What it does is resolve to a pre-determined URL, so even though your IP address changes, the URL re-syncs with the Deerfield.com DNS server and nobody notices a change as long as they address your server through the URL.
I use it to basically keep my home server resolved all the time, but I've never used it for business purposes. Should work OK, however.