Know the limitations of an Embroidery machine before you buy it.
Many folks interested in learning how to use an embroidery machine buy the Brother SE 440, as a "starter" machine to see if they can learn how to do machine embroidery. They purchase it without doing much research about what they can or cannot do with a machine that only has a 4" hoop and cannot be upgraded. The majority of embroidery machine design packs for purchase are for a larger hoop size, typically an 8" hoop.
Before buying ANY embroidery machine you need to learn a little bit more about Hoop Size before choosing to spend that much money on a machine.
It is the most common reason that bottom of the line model is for sale in huge numbers, in nearly brand-new condition on the used market, check CraigsList...... folks buy it and sell it in brand new condition because you can only do basic letters (monograms, etc) and very small sized stitching designs.
Go to a sewing machine center and test the machine you want to purchase and ask a lot of questions. Ask the dealer to show you the largest designs the machine you are testing can embroider. Each model and manufacturer machine has its own "maximum hoop size" and you cannot stitch with a bigger hoop on a machine designed for a 4" or 5" hoop. The majority of designs available for purchase are for 8" hoops.
If you want to use any ®Disney character stitching designs, Brother is the only manufacturer licensed to sell Disney character and design patterns for Embroidery machines.
Buying a used Embroidery Machine should involve more than base price and if it works.
Are parts still being made for it, are they more expensive than the purchase price?
Is there anywhere local to you that services that model?
Are there any YouTube videos for how to do procedures with that model?
Is there an active User Support Group for that Brand and Model?
Save money for longer and buy a machine with the biggest hoop size you can afford. Save yourself by learning from others' bad experience.