I'm not sure about MA but in CA we test approx 2 a month at $67.00 a pop which includes $52 for the test and $15 for the collection. You can go several weeks without a test however then get hit with two or three in a row.
As far as traveling - Again in California all travel must be approved and test site are arranged - if no test site in available they may not test you while you are gone but you will be tested soon after you return.