I've been to Thailand 3 times (solo) and it's been amazing! Don't hesitate to travel there on your own if you're curious. It's easy to get around and the fun places are open and accessible. Absolutely no worries!
LINE is a great app to have over there and very popular. I never bought a new Sim card and just relied on the free wifi from hotels, coffee shops, etc.
Your first visit, I'd highly recommend Nana Plaza in Bangkok. When you get off the plane and clear immigration, exchange some cash at the airport & head to the taxi stands. Destiny Inn is a great hotel right next to Nana Plaza & they offer a free shuttle to their hotel in Pattaya if you stay there. I'd suggest at least 1 night in Bangkok, followed by several in Pattaya. You can always change hotels after a few nights if you find a better one.
Nana Plaza is a 3 story mall with probably 30+ bars, each having 10-100 girls on the stage. It's more expensive than other options, but the experience and choice make it absolutely worthwhile!
Pattaya is adult Disneyland. Street after street of little bars & massage shops. You can literally get laid here so much that it gets boring. There are a LOT of girls to choose from, and you can find everything you want.
It's not hard to find a hot girlfriend in Thailand either, although the bar girls are not recommended for this. I actually wouldn't recommend this for a first trip, but maybe later you'd want to find a non-pro 20+ years younger than you who wants to be in a real relationship. It's not at all difficult to find.
Yes, every situation costs, even a real relationship, and "gifting" small amounts of cash is common when in a relationship there. It's more symbolic that true support.
My 2nd & 3rd visit to Thailand was a few days, and then a week with an absolutely stunning girl (and I can't overemphasize that; truly model quality & the best body I've ever seen) who left me weak in the knees and completely drained. I met her online and we talked for a few months before my visit. I went to her hometown & house, met her family, visited her at her day job, drove her car while she was at work, and we spent every evening together. Yes I paid for everything (food, tickets to Phuket for a few days on the beach, hotel, etc) and gifted her the equivalent of approx. $300 U.S. (which she never asked for) just before I went home, but I got laid FAR more than any other week in my life, and spent much less than on a pure mongering vacation. And it was a much different experience. I don't want to say she's a holiday girlfriend... but yeah.
Although a lot of girls you meet will be playing all the foreign guys they can find, that's not true for all, and there ARE some truly sincere and genuine sweethearts out there! She still keeps in regular touch and begs me to return.
However, there's a lot to be said for a brief experience, paying a few bhat, and then they leave. Wash, rinse and repeat as much as you want. I never minded at all when I'd take a solo morning walk on the beach in Pattaya, drink a coconut water, eat lunch at Hooters, visit a spa or a "soapy" (... my gawd, what an experience THAT is! Literally a buffet!) take a nap, and then head to walking street after dark or find a freelancer on beach row.
Bottom line is that Thailand is THE absolute gold standard. It should be something every guy experiences. Asian girls from Laos, Cambodia, Philippines, etc. will all travel to Pattaya to make their fortunes and maybe be "saved" like Julia Roberts in Pretty Woman. You don't have to fly all over Asia to have the best selection available, the all go there like it's the Mecca of hedonism.
If you have ever wondered what it feels like to be a Rockstar, GO TO Thailand!
