There is no harm in getting yourself 3 estimates. By the time you're finished talking to the 3rd contractor, you'll have a lot of questions answered AND a few more to ask the first 2 contractors! This is part of the education process.
The exact material you use, the location of the patio, the type of 'ground' you have, the 'location' of your home, and others, have an impact on the price. After you've spoken to the 3 contractors, you'll be asking yourself, "Why is Contractor 1 30% higher than Contractor 3???" That's why you get your Estimate in writing. Hopefully, they 'itemize' your material and labor for you. Contractor 1 may use stone dust for the entire job vs. Contractor 2 may use stone dust as a base and SAND as a mortar. You never know! Once you learn about the 'process' of installing a brick patio, you can ask the questions about the 'in between' parts of the job, like do you use sand, do you use gravel, how deep do you dig, do you allow for drainage, etc., etc..
Enjoy the education! You'll be all the wiser. :) My best to ya and hope this helps.