All my designs are stored on external drive (passport). These are available at the office supply stores less than $100.00.
There are 1,000's of designs on mine and the storage capacity is still generous. You also want to have an extra back-up every 6 months or so depending on how often you add more designs.
Then I just move the individual stitch designs onto the USB for your machine. New technology in EMB machines allows wireless downloads from the computer. No USB needed. Fun stuff!