Almost any machine will work on these light fabrics that we use in our DIY projects. The only time you might want or need a heavier machine is when you are working on thick straps for backpacks or tree straps. Generally speaking most people in this forum will suggest not spending a lot and look for used machines that will do the trick. Borrowing machines from a grandma or otherwise is a good way to get a hold of a great machine for basically free.
Buying something new is an option but what I ended up doing was browsing through craigslist. I found a lady selling the following machine for 75 dollars.
https://www.amazon.com/Janome-2212-S...=janome+sewing
It was basically new since someone purchased it for a class and never even used it. It was also freshly serviced. I came away with the machine for $50 dollars after some easy negotiation. The machine can sew through thick straps and all the stuff I could possibly want for a DIY project. It doesn't fuss over tension like some other machines I have worked with. And best of all, all it took was about 30 minutes of browsing Craigslist.
My suggestion is not to invest a lot! Try to find a bargain by borrowing or purchasing something used. Some of the very old all metal machines are a huge bargain and perform their job better than most new machines! Keep your mind open.