Payment and Billing


I don't charge for the first one-hour session. After that, my rate is $100/hour. Please pay on the day of your session or before. You are welcome to pay for any number of sessions in advance.

  • Online

    Most of these online payment methods require my email address. It's my first name Contact me if that's confusing.

    • Zelle. My favorite way to get paid is a bank-to-bank transfer via email address using Zelle. (Please use my email address, not my phone number!) Often you can use Zelle via your bank's online banking app; they have partnerships with Bank of America, CapitalOne, Chase, Citi, Citizens Bank, TD Bank, Wells Fargo and many others, and I'm told you can use it even if you don't have an account at one of their partner banks.
    • Dwolla. For more info and to sign up, visit To pay, visit this Dwolla payment form.
    • venmo or popmoney. Just sign in to venmo or popmoney (if you don't have an account, create one first) and send the payment to my email address.
    • PayPal
      • PayPal (easy way): Please use the button below to pay me online with either a credit card or a PayPal account. After you press the button, you should get a Paypal form. Here's what to put near the top:

        • Description: the student's name
        • Unit price: whatever you owe

        After that, choose one of "Don't have a PayPal account" (to use a credit card) or "Log in to PayPal" (if you have a PayPal account) and follow instructions.

        I never see your credit card number; you only need to trust PayPal with that.

      • PayPal (preferred method)

        If you have a PayPal account with a balance, I'd appreciate it if you'd pay me a different way: Login to your PayPal account and click the Send Money tab. Put my email address in the To field, fill in the amount field and choose I'm sending money to family or friends. This should avoid PayPal fees.

  • Check/bill payment from your bank

    I'm happy to accept payments by check or online bill payments from your bank, which arrive here as checks. Please send to Jon Dreyer, 81 Baker Ave, Lexington MA 02421-6228. Don't worry about an "account number" if you use bank bill payment.

  • Cash

    Cash is great, preferably in person. Please make sure I note your payment before you leave!


I usually don't send bills because I ask to be paid in advance. However, sometimes things get complicated and I send an invoice, usually by email, and you can always request one. I always appreciate another set of eyes. If any of it does not seem right, please let me know.

By the way, this is my own homebrew accounting software. First it exports my calendar to a spreadsheet, then processes all those calendar sessions along with a spreadsheet of payments and some other stuff and cranks out invoices. The first part is written in Google Apps Script and the rest in Ruby. Aside from fun (really!) the main reason I did it this way is so that I don't have to enter all the sessions once in my calendar and then again in some accounting system. This also means we need to be extra careful that my calendar is correct.

Thank you!

Jon Dreyer • Math tutorComputer Science
781-696-2614 • 81 Baker Ave, Lexington MA 02421-6228 • email

I have no special talent. I am only passionately curious. —Albert Einstein