In his book 'The Lean Start-up', Eric Reis talks about the concept of 'minimum viable product'. Launching with the minimum viable product, can be a good way to test the market for a product without investing lots of money. However - to your point - you need to be careful, especially in a service business. Even your basic offering still can't turn off customers. My suggestion is you find other ways to figure out if there's market for your service. For lots less than $100,000 you could even engage someone to do the market research for you.