I recommend Monkey Grass - Ophiopogan japonicus . I have it growing between bricks in a walkway & it's proven to be very tough. It survives summers of 100 degree weather in the sun, needs only water and is oblivious to insects or disease. There are two "sizes" and two colors: green & black. It's safe for USDA 8-11; Sunset zones 5-9, 14-31, warmer parts of 32 Here is a link that might be useful: monkey grass

As long as the planting area drains well, you have a lot of options - Leptinella squalida, any of the various creeping thymes, rupturewort (Hernaria glabra), Scotch or Irish moss, blue star creeper, etc. Any of these will need periodic watering this season after planting and occasional irrigation during the driest parts of the summer thereafter but should tolerate the rest of our weather fine.

Personally, I like the low-growing veronicas, such as V. pectinata and V. prostrata. They'll spread, but they're easy to control. I've used thyme in the past, but have found it too invasive.

Nobody has pricing per square foot other than the actual material cost. Every contractor is different in their costing and of course the site prep will up the cost as well if there is a lot of excavation to do. If you have experience with travertine pavers, I think the Artistic pavers are about the same material cost wise. I believe these are only 1 1/2" thick like travertine and cannot be compacted like regular pavers, so the installation has to be perfect. There are also no joints for sand. They do look pretty cool for a more commercial look especially if you want to go with the lighter colors. Make sure your contractor has experience laying these pavers as they are a bit different in installation technique. You might also check into a new line of porcelain pavers by Belgard called Monarch, very cool, but not cheap.