If you don't need to measure frequencies over 20 MHz a portable USB scope with a very affordable price tag of about $60,- can be a very nice tool. A laptop or an Android phone / tablet serves as display.
I recently got myself the Hantek 6022BE and I am very pleased with it. The video shows an overview of six diferent software apps that are available for it. Future video's will go into more detail on the individual apps.
Link to Hantek 6022BE Overview of Six Software Apps
