It might be pretty simple to the most of you, but I want to calculate what motor I can use for my project (and find out if there even is an affordable motor that can deliver the speed and force I need)

I'd like to lift a person (assume 100kg) 50 cm high with a speed of 30cm/s...
Just straight up, no moving sideways.
The motor wil be right below the person's feet, so no extended arm.

I hope this is enough info to calculate something or at least help me in the right direction

 

Generally you make the mechanical device to suit and then measure the initial static torque required, this can be done in a few ways from a line and spring scale, to a automotive torque indicator wrench.
The motor torque would then be based on this measure, if necessary a gear reduction could be added etc..

 

good place to start is to use an online calculator to see how many watts are required to perform the main task. The method chosen to acquire the linear motion will suggest efficiencies.