Rosalyn is a single mother with two children ages 3 and 5, and she lives paycheck to paycheck. She is trying to save money for a Christmas present for each of her children. She does not have a checking account or a credit card. She wants to get each child a bicycle with a character from their favorite TV show, but the bikes are $100 each. She only has $50 and is afraid that by the time she saves another $150 those bikes will have sold. What payment option would you recommend to Rosalyn?