There are thousand of Hotels in Bangkok.
Yes you will find places under 1000 baht.
Not sure about international booking fee?
Most hotels I book I try to pay in cash on check in or check out. This saves me using my debit card and my bank fees.
This will get you started peeking. Agoda, a booking site that can filter specific budget. Use ฿750, which doesn't include tax / sc (7 / 10 %), which will add up to about ฿900 THB / $30 USD. (B31 to $1), should be no booking fee, or int'l charge.
Filters; price, pay at hotel, near transport / rail lines, though not sure how accurate that filter is. I prefer Booking.com, but check both sites, along with hotel sites. Booking sites have verified reviews of actual clients, TA / anyone can review.
Hotels are booked per night, NOT per person. Also verify location via Google map, make sure they agree, along with some more photos and reviews. Can even stroll around the area with GM 'Streetview'.Edited: 12:08 am, June 09, 2018
You could consider At Mind Executive Suites for about 920 Baht a night on Agoda. At Mind Executive Suites is near Onnut BTS station. Onnut area offers low cost hotels, Tesco Lotus market, Big C, K79 currency exchange shop, Onnut French Market and street food.
You should narrow down where in Bangkok you want the hotel. Bangkok is a huge city, maybe 6 times larger than your own city.
Forum search with a laptop or other big screen computer will give you many posts for hotels in various locations throughout Bangkok. You should start quoting prices in Thai baht. (Forum search and reading the FAQs will give you help with changing money. Even a Google search will give you a rough estimate for what $30 is in Thai baht. Figure on around 900 - 1000 baht.)
If only using a phone for research switch to a real computer and the research will probably make more sense.
Lub D Hostel?? Private rooms available.
* Take the time to look over WHERE you want the hotel located. Then choose a hotel in your price range in that location.
Prices higher during "high season" especially close to Christmas - New Years holidays.
Good luck.Edited: 5:47 am, June 09, 2018
**You should narrow down where in Bangkok you want the hotel. Bangkok is a huge city, maybe 6 times larger than your own city.**
What are your plans in Bangkok? Shopping? Nightlife? Etc.
Asking for the "best" anything in Bangkok will get you hundreds of answers.
I normally use Hotels.com for booking my hotel rooms as I find their website user friendly and also the price shown is the price you pay. All add ons already added into the price so no hidden extra costs.
I think if you can narrow down which parts of Bangkok you want to stay in, it will help to provide suggestions of hotels for you. Maybe also include what is important to you as far as hotels go such as transport links, breakfast included, pool etc.