Creating Radio button or drop down with different prices before clicking pay

[Tweek79]

I have been looking all over the site for an example of how to have 4 options of different payment amounts. 

So say Plan1 $10 , Plan2 $20, Plan3 $30, Plan4, $40

After selecting a radio button or selecting a plan in a drop down you then click pay and it sees what item is selected and makes the payment that amount.

Client side Rest API

Thanks in advance.