Great question,and welcome to embroidery. I suggest to get started:
- some 11/75 needles,
- some tear away and cut away backings (stabilizers)
- the manual for your machine if you don't already have it (the manual for the Bernette Deco 500 will do too; I understand they are the same machine)
- some ideas for embroidery projects you would like to do
- some embroidery thread. Regular sewing machine thread does not work.
- white bobbins for your machine. Check the manual to find out if they need to be A,L, or M class bobbins. My research indicates you need L for this machine.
Your machine comes with built-in alphabets. I suggest you try monogramming a few things with those. It also has some built in designs. Look them over. Try them out using your fabric and stabilizers, thread, and bobbins.
Your machine has the ability to read designs from cards. If you want different designs from the ones already on your machine, you will need a card writer box, and the software to write cards, and some blank cards. Since you bought it used, you may or may not have the original box, card, and writing software (the software is for your computer, so you can write designs downloaded from designers onto your card). If you need a box and writer, look into the Ultimate Box, which we have on Embroidery.com. We also offer many designs you can download and use.