There's no competition. For simplicity, ease of use, portability, cost, and versatility, the Pull Up Mate is the only option.
For about the cost of 1 month's gym membership you can get yourself a 2m high free standing pull up bar to use at home to practice a huge range of exercises on. The Pull Up Mate is second to none in its portability and ease of use. You can assemble it in minutes, and pack it under your coffee table. Unlike the monsterous power towers that can only be placed in a garage or gym, the Pull Up Mate can be used anywhere; in a sitting room, the dining room, the office, or even the bedroom.
Pull Up Mate UK