several of casts fixtures alone exceed the 200 per fixture cost that gets batted around. they put a lot of know how and materials in their product. that being said, there are tons of online companies that sell decent product, along with an irrigation supllier that must be near you or at least within 50 miles from you.
Volt is a good name out there to research, as well as copper moon and FX.
when you bid, add up your material costs, your labor costs, and then figure out what you need to make to run a business and pay yourself for however long you work on the project. we run from anywhere 200-400 per fixture cost, depending on how much wire we use, LED or non led, how much built in expansion room in the trans and wire we install, honestly how far we have to drive and how far the fixtures are from the trans, concrete cuts, etc. all these change bids dramatically.
the more you bid and do jobs the closer you will get to understanding time and materials to do a job. but until then I would not go below 200 per fixture and a minimum of 6 fixtures.