A third option is to pay for each machine that runs the hosted application. Look for an ASP that can be flexible. A good SLA should address availability, response time, reliability, and error rates. Then pin the ASP down on any startup fees or upgrade costs it plans to charge. Also review the contract as far as help desk support.
Some ASPs charge fees for placing support calls.
These ensure that you retain the right and access to proprietary data and applications and that you can get uninterrupted service elsewhere in case the provider goes under. But even with all of these safety measures, don't get suckered into signing a contract longer than the usual 18 to 36 months unless you're sure that the ASP is on solid financial footing. It has a very strong client base, high visibility and is a pretty safe bet. Fill in this form for your free trial issue. U.S. indexes are real-time.