Whoa, whoa, whoa...

You are trying to figure out how to save $1 on cab fare into the city but then your plan is to move hotels three times while in Bangkok??? You do realize changing hotels via cab is not simple? Riding from hotel to hotel in a cab will be a nightmare. I once had to go from the Marriott at Soi 57 to the Renaissance, which is 5 km straight down a single road, and it took over an hour. And again, you don't want to pay a negotiated fare because you don't know the roads or the traffic so you will always lose that negotiation. Always. Try to get your stuff into a single easily transportable carry-on and take the train from hotel to hotel during off peak hours.

It's your trip, but why spend six extra hours packing, checking out, taking a cab and moving to a different hotel? I've done it for extreme price differences on last minute trips, but only once per trip and I've often regretted it. If I'm reading correctly, this is your first trip to Bangkok but your are going to attempt tricks that many of us who have been there numerous times are telling you are bad ideas. You've gotten very solid advice here. There is an old Cuban expression that roughly translates to "The cheap becomes the expensive." You are setting yourself up to realize why this is an oft repeated saying.