This is likely why they say the option you choose will not impact how much money you are given. If you choose $50/week, and are then offered $5/week and take it

This is likely why they say the option you choose will not impact how much money you are given. If you choose $50/week, and are then offered $5/week and take it, they know you were overestimating. The study wants to learn empirically the relationship between perceived and actual willingness to abstain from Facebook at various price points.