I agree that a reader/writer box will open up many more designs that you can download. I have PED Basic which runs about $100 and comes with 1 blank memory card which can be used over and over. I also agree that in a short time, you will be ready for a hoop size larger than 4x4. I have a 5x7 and it works great for many designs. If you buy a "refurbished" machine from a reputable dealer, it's almost better than a new one because many of the "bugs" have been worked out.
If you can afford one, I would get at least a 5x7 hoop size and one that uses a USB port you can use with a computer. So much easier to download designs from the internet. A couple of good stores that carry refurbished machines is AllBrands in LA and Ken's Sewing Center in AL. Great customer service.