Portable hangboards: install it anywhere with an easy setup and start training for rock climbing wherever you are. These fingerboards also have the pro that you will train core muscle as well as finger strength.
They are the best option if you do not have much place (you can easily install it on a beam) and, even though they might not have the same hold variety of a standard training board, they will do much for your finger strength, for your balance and for your core strength.