Multiple price for one contact form

I want to add multiple price to one contact form, like $25, $10, $5 etc, as I am selling different memberships using one contact form, and in contact form I have provided 3 options to purchase either of the items.

Is it possible to define more prices in one contact form? I have tried following formats so far

25.00 10.00 5.00
25.00, 10.00, 5.00
25.00 | 10.00 | 5.00

None of them worked.

Thanks for your help