Not really...
First things I'd say is that, taking a look at what
Toolstation offer as an example, is that a lot of these cheap guns are advertised as "stapler/nailers" and only take 18 gauge pins. The problem with being a stapler/nailer is that the end of the drive "pin" has to be wide enough to drive not only an 18 gauge pin, but also a 6mm wide staple - so every time you drive a pin with a gun like that you get a 6mm wide ding in the surface of the material which has to be filled - a dedicated 16 or 18 gauge nailer makes a far less noticeable mark in the surface. Secondly they often only accommodate short pins, up to about 35mm, whereas you need 40 to 45mm pins to hold architraves in place, and often you need 50 to 65mm to hold skirtings in place - which really means using 16 gauge nails, not the 18 gauge these guns are. From what I've seen of these in the past they are also pretty gutless, so they will struggle to drive pins into hardwood, for example. Those are some serious limitations to my mind
If you want an alternative at under half the price of a pro nailer, you might want to consider getting a small portable compressor, like this
Stanley from B&Q, this
Einhell from Toolstation or this
Bandit from
Machine Mart in the £100 to £130 range, then add a decent 16 gauge 2nd fix nailer from a respected manufacturer such as
Senco, Bostitch, Paslode, deWalt, etc. That puts your budget in the £200 to £250 range, but a small compressor has a lot of other future uses, e.g. tyre inflation, running a pneumatic drill, running a 1st fix gun for fencing (I had a cheap B&Q Rockwell compressor which did that for years), dust blow gun, etc. Still more than the cost of a week's hire of a 16 gauge Passy, though