The Maker Box easy plan features 4 samples of filament in different colors from a single manufacturer each month. The samples are normally 50g / 16m but some manufacturers will offer bonus lengths of up to 75g.
The material will be PLA or something that prints at typical PLA settings. No special nozzles, enclosure, or heated bed.
This is the plan to pick if you don't want to try challenging materials and your goal is building a library of color choices with easy to use filament.
The box ships on the last Tuesday on or before the 25th of the month.