Finding a decent bass guitar under 100 dollars isn't the easiest thing to do, but I want to show you five guitars that will allow you to learn, play and give you a good sound. These are instruments designed mainly for beginners or playing for fun and at home. I've chosen these based on mostly feedback and reviews from players that own them.
These instruments are durable and should last for years. They look good, have a decent sound and many come with a gig bag, chord and other accessories. One of those listed below even includes an amp.
The instruments below were chosen because I've heard they are well built and will allow you to learn while adhering to your budget. These all come in at around $85 to $99. That's a good price these days for a product that gives a beginner and home enthusiast a lot of fun and definitely provides a good enough sound for all rookie players.