How to set Paypal along with other payment options

In the "sign me up for the seminar" portion, would like to have the options of: One-time payment, 4 equal payments, check/money order payments. We were able to insert those options on the form itself, but cannot register anyone who is not making a payment via PayPal or CC.

Considering that you are using Paypal payment inside of your form, those are only options for your user to register. How ever you can set up Paypal along with other payment options. Inside of this article you can find out how to do it:

http://www.jotform.com/help/120-How-to-set-up-paypal-along-with-other-payment-options 

However if you want to allow your users to submit your form without paying for registration, you can use conditional logic to hide/show payment option inside of your form.

Here is a demo form I made where I set conditions to hide payment option:

http://form.jotformpro.com/form/51585651798976? 

Feel free to clone it for closer look.

Hope this will help. Let us know if you need further assistance.