What is 3D printing? There are 3 main types of 3D printer with a few weird and wonderful off shoots like printing a house with concrete.

Fused Deposition Modelling (FDM) printers:-
FDM printers use filament (typically 1.75mm) to print the model in layers using various materials (most commonly Polylactic Acid, PLA).

Resin printers:-
These printers use a liquid resin and cure each layer using different methods. The cheapest use a UV light source and a LCD screen, Masked Stereolithography (MLSA). Digital Light Processing (DLP) uses a projector and Stereolithography (SLA) uses lasers.

Sintering Printers:-
These use lasers to melt normally a powder and are called Selective Laser Sintering (SLS) but come under other terms as well like Powder Bed Fusion (PBF) and Direct Metal Laser Sintering (DMLS).

FDM printers are the best entry level printers with a price range of £100 - £3,000. They are good all rounders.

Resin printers are a little more complex with a price range of £300 - £15,000 and are better for characters/figures (D&D etc.) but need more post production (cleaning and curing etc.)

Sintering printers are are more Pro and manufacturing and typically expensive. A Nylon powder one would cost £17,000 for the kit. Never found a price on the metal ones = very expensive.