Depends on the cars condition and if it only looks like an R/T or also has an according drivetrain, suspension etc.
You looked at other mopars as well? I personally prefer the 1970 coronet r/t over the 1969. (Because of how it looks)
You probably know but if not also look at things like 68-70 Dodge charger, 71-74 Dodge Charger, 70-74 dodge challenger, 70-74 plymouth cuda / barracuda, 71-72 plymouth road runner / gtx...
or even some fullsize cars like 69-72 plymouth fury, 69-71 imperial, 69 dodge polara / monaco
depending on what you want.
There are lots of great cars out there so dont just buy the first one that pops up.
Also do you need the performance of an R/T (or Super Bee, Road Runner, GTX in that regard)?
You could save a ton of money with a base model and still have 90% of the fun.
If in doubt go for the top of the line model.
The R/T and GTX are the top of the line models by the way.
Super Bee and Road Runner are cheaper models which only focus on performance.
So if you could not afford an R/T but still wanted to go fast you ordered a Super Bee for example...