If the .20 planes are your only choice, the freedom 20 is the only real choice because it is the only aileron trainer of the three. You will outgrow the other two planes a lot faster. Don't be scared of the ailerons, they are easier to learn than you might think.

Like Newrc stated it is better to go with a .40 sized trainer because you can swap out the engine and radio for future planes.

.40 trainers for the same money include the Great Planes PT-40, and the Tower Trainer 40 Kit.

For the price you might want to consider getting the Tower Trainer 40 ARF, and a kit for your second plane. That way you can start flying, and about the time you outgrow the trainer, you have your kit build ready to transfer your engine and radio. The Tower trainer ARF costs 65 dollars, which you can't buy a kit for that, and on any kit, add 60 dollars to that for covering, glues, tank and other items not contained in the kit.

The most common engine to use is the .46 and get one with ball bearings.

And get as much radio as you can afford. 4 channels minimum 6 channels or so if you can afford it. You might not use the extra channels now, but you will later. The extra channels can be used for flaps, retracts, bomb drops, camera shutter... the list is almost endless.