There are hundreds of listings of completed cross stitch designs on Ebay. Trying to decide which one is right for you can be easier if you take a minute to consider the following tips:

1. Personal taste. If you see a design you absolutely love, then it is probably worth looking at closer.

2. Materials used: Cross stitch worked on linen or evenweave are higher in quality. The thread lays on this fabric much better than Aida cloth. It makes a smoother appearance to the design. It is also more expensive for the stitcher to use. Hence, if the price is higher, part of it comes from the type of fabric used. Anytime you  see a design stitched '1 over 1', it is a special piece. '1 over 1' refers to 1 thread of floss over 1 thread of fabric.  This requires the stitcher to make very tiny stitches and it is meticulous and time consuming work. Several patterns call for 1 over 1 on just the face or hands. The rest of the pattern is 2 over 2. This is still a high quality piece of work and should be regarded as such. 

3. Appearance: Has the piece been cleaned and pressed? A caring cross stitcher will make sure it is clean and press it before offering it to you. Are the edges of the fabric free from frays? I used to use fray check on all my items, but have changed to serging the edges. Taping the edges leaves a sticky residue when removed and hard to wash out.

4. Reverse side:  Some stitchers choose to show you the back of their work. It is a good thing. If you don't have a chance to see the back side, examine the piece when you receive it. Turn it over and look for knots, long threads or a messy appearance. This will tell you how carefully your cross stitch was stitched. A neat appearance without knots is a good sign. Of course, if the pattern calls for a lot of color changes in a small area of stitching, the appearance may look a  bit messy, but knots are a no-no in any event.

I hope this has been helpful to you. I have cross stitched for over 28 years and am still stitching. I have offered many pieces for sale on Ebay and have had tremendous success. I hope to have more pieces for sale in the future. It has been great meeting people all over the world through my cross stitching.