A really simple Magento 1 extension that allows to sell offline vouchers with a freely selectable amount.
No configuration required.
To add a voucher, simply create a new product and set the "Is Voucher?" attribute to "Yes". Also add a custom option where the customer can enter the voucher amount. This can be either a dropdown or a text field.
Most of my repositories posted here are projects created for customization requests for clients, so they probably aren't very well documented and the code isn't always 100% flexible. If you have a question or are confused about how something is supposed to work, feel free to get in touch and I'll try and help: info@mobweb.ch.