The price will be an indicator of what you can do with the robot. So the cheapest may not actually be the most cost effective.
MakeCode does have a version that works with a micro:bit. And micro:bit has many robots to choose from. A micro:bit should cost you about $20 US if you look around. There are many other controllers but, you will need to figure out if they are compatible with MakeCode. It is often the case that a robot and micro:bit bundle are actually more expensive than buying them separately, check the price.
I have tried a few different robots.
My current favorite is Elecfreaks Cutebot Pro. Currently sold out at Amazon . Priced at about $50 US. What is notable about this robot is it has grey scale line tracking sensors and encoders on the motors. That means you can do some more advanced stuff with it. It uses one 18650 battery. It is not the smallest robot, but not the biggest either.
My previous favorite is DFRobot Maqueen Plus V2. This robot has grey scale line tracking sensors. It also has many accessories available like an AI vision module. Also priced at about $50 US. It is not available from Amazon. There is a version that takes 4 AA batteries or one of the 18650. You can see some projects with this robot here https://www.youtube.com/@jdonwells.
The Maqueen is no longer my favorite because the MakeCode extension has a bug and it has not been fixed for a year and a half. The extension has been updated for a new V3 version of the robot which is different from the V2 version. I would not get the V2, I would wait to see what the V3 is like.
Elecfreaks does have a Cutebot version that can be has at Amazon for $30. It doesn’t have all the bells and whistles as the Pro version but it is a nice little robot with many expansion possibilities. I have used these but do not own one. This robot uses 3 AA batteries.
Yahboom has the tiny:bit and I have one. It is also $30, but it does not have the expansion possibilities of the Cutebot. This robot uses one 18650 battery.
The other robots I have purchased and tested are either too expensive or don’t have enough sensors built-in to be cost effective.
One notable robot is the Kitronik :move robot. This robot has a place for a pen so that you can draw with it. However, without motor encoders you can’t do much drawing anyway.