everything is done online. Once approved, your consulate that services your paperwork emails you the visa paperwork which you present to immigration in Thailand with your boarding pass.
Your question: “Is there a way to keep my American number without paying $45 a month?” - unfortunately once you cancel service, you will loose that number. But - read here:
Yes and one of their locations is at the Trendy Building located on Sukhumvit Soi 13 with easy access to both the BTS Nana Station or MRT Sukhumvit Station not far from Terminal 21.
Use Expedia or similar sites to seek out the airline that flies business class from the airport you will depart from. If you find that reasonable fare, go to that airline’s website to compare the fare and if ok, book directly with that airline. If any issues arises, working directly with that airline gives you better results that with a 3rd party (Expedia and others).
A known scam when you give up your passport to the cycle rental shop: They will claim that the cycle you returned is damaged or this or that and won't give your passport back until you pay a "ransom" repair cost. Or they follow you, steal the cycle back and you return to the shop to report the loss and forced to pay a high cost to settle the bill and you passport will be released to you. Please no trolling on my comment