What are the options for luggage storage in Bangkok for travelers?

I used airportels in suvarnabhumi B floor. They’re also in don muang and even some shopping centers. Caution: if you ask staff for directions, they might understand airport hotel and direct you to the hotel which has an entrance in the same floor. They even deliver the luggage between locations and to/from your hotel. I left my wheelchair towing machine with them. You can take the airport rail link easily with you carry on right next to their counter

Main bus station aka Mo Chit 2 has luggage storing services. It’s the most cost effective, convenient location too. I’ve used it on my most recent trip to Thailand about a year ago.

I left my case at the left Luggage in DM airport. 11 days cist me 850 baht

You say you want to base out of Bangkok, which means you'll be going other places, but returning to Bangkok from time to time. There are a number of hotels that will store your large bags for free, as long as you stay with them when you are in Bangkok. Lots of people touring South East Asia base out of Bangkok, and use the same hotel for this very reason. You can't do this with Airbnb.

There surely will be. I'd rather be interested in the cost. Is it cheap? regular? expensive? Any experiences?

@Said ******

both dmk and Suvarnabhumi airports have plus many public ones throughout the city

There are places. I used one on my first visit to Thailand in late 2022. I can't remember the name of the place I used, but not knowing either the country or city at all, even with the aid of Google Maps I couldn't find it. It was only thanks to a very kind Thai man that spoke no English. He saw me going back and forth, looking a bit lost, suitcase in tow, he realised what I was looking for and directed me to where I needed to be. I was planning to visit The Golden Palace that day and the storage place was only about 5 minutes walk away.

Do an online search and you will find a few organisations that you can book through. To avoid the same experience with finding the location when you're there, I suggest that you book storage at a decent sized Hotel or Shopping Mall or the like which is easy to find. The place I booked, turned out to be in a small side alley and there wasn't any signage to indicate where it was.

Most bus stations and rail stations have left luggage storage

Also Don Muang airport in Bangkok has one