i got my optimus s though ting, if you already have a device then ting wont work for you, but if you need a device they offer the optimus s for $150, but i was able to get $50 off the device though hak5, but while that did save on the device i ended up paying like $60 for my first month of plan, and onetime activation and all that jazz. but ive been fairly happy with it. whats cool is if i dont have money or running close to what i can pay as far as my plan goes, i can just turn off what im running close to. like if i only wanna pay for the basic 100 text messages, if i get to 99, i can turn that off on the website. same goes with the voice and the data. the plans are pretty cheap as well. the small plan, costs $15, $3 for voice - 100 minutes, $3 for texts - 100 texts, $3 for data - 100mb and $6 for keeping your phone activated. for $15 thats not bad.
anyway hope that helps.
i forgot to mention, that you can do tethering right off the bat, no rooting, or paying extra, as long as you pay for the data, they dont care of you tether or not.