Unfortunately, there are few Ready To Fly RC gliders available compared to powered RC planes, and this is a shame for beginners who just want to get flying without any assembly fuss.
It seems that the only RTF gliders around are of the powered variety. Presumably, this is a reflection on market demand, and in my opinion it’s a shame that at least some manufacturers aren’t offering a good selection of 2 or 3 channel RTF gliders for sale.
An Almost Ready To Fly (ARF) glider is the next best option but obviously, you’re going to have to buy, install and set up the radio gear yourself. A certain degree of aeromodelling knowledge is required to complete and set up an ARF rc aircraft, but if you’re completely new to the hobby there is plenty of help around.
The range of scale gliders from Seagull is a good one, and the quality of Seagull aircraft is very good. Having had a couple of their aircraft, I can vouch for their quality.