I agree with @Claes here, a desktop computer would be cheaper/more powerful.
However, I have indeed bought last year a laptop because I needed something to bring along and still be able to perform well during weekends away from home. At home it’s more or less permanently hooked to a good 27" monitor, but if I unplug it then I can carry on working on my photos wherever I go.
It is a Dell XPS 15 model 9560 (I believe it’s a 2017 model), bought second-hand for around ~1300 euros in September 2018. The GPU is a Geforce GTX1050; no comparison with my previous laptop which was a Thinkpad with the onboard Intel GPU (similar to Anna’s HD520 I think). The cpu is a Kabylake i7-7700HQ@2.8Ghz, 16Gb of ram, fast 512 GB ssd.
I have had plenty of things to tinker around using Linux/Ubuntu but overall I’m happy now with the performances. Especially after having installed yesterday Darktable 3.0rc, wow – superfast!