EM shuffle alleys in fully working condition, with reasonably good cosmetics, top out in price around $500. If the backglass is cracked, broken or has substancial paint loss, but otherwise fully working, its worth $100. Backglasses are nearly impossible to find for EM shuffle alleys. Nonworking EM shuffle alleys in reasonably good cosmetic condition start out at $100.
Solid State/DMD shuffle alleys in reasonably good cosmetic condition that are fully operational bring $600 - $800.

Few people undertake high level restorations of shuffle alleys, simply because they will never ever sell for whats invested in them. Yes, one will see all kinds of insane prices for shuffle alleys on craigslist & ebay. They rarely sell.

Here is my take on ball bowlers. Any ball bowler worth owning is an EM. If you see an EM converted over to solid state.....run away.....quickly.
Pricing. I happen to think $600 - $800 is the absolute maximum one should pay for a non restored non-working ball bowler. If its in storage, and the seller insists it worked fine before being put in storage, it shall be considered a non working ball bowler.....and priced accordingly. Mechanically, shuffle alleys & ball bowlers are almost identical.....obviously pucks bounce back & balls have a ball lift mechanism.
Professionally restored big ball bowlers (heavy emphasis on PROFESSIONALLY), can bring over $10K.
Small ball bowlers were produced in 1956 & 1957. They are by no means on the high end of the pricing spectrum, but rather on the low end. The high end of the pricing spectrum is for 16' or longer big ball bowlers. Highly sought after ball bowlers are any of the 63-69 Bally Ball Bowlers as well as the 1960 United & MBA Bowl-A-Rama.
Ball Bowlers were produced from 1956 - 1973. United & Chicago Coin are the most common with Bally a far distant 3rd. There is a trade off on ball bowlers. Many find the ball bowlers prior to 1961 the most desirable for aesthetic reasons. I happen to think certain Pre-1961 United Bowlers with curved pinhoods & attractive females on the backglass are tops. As ball bowlers evolved, females disappeared from the backglass, but game variations multiplied. Certain models of the early 60's Chicago Coin bowlers also are very aesthetically pleasing & offer many game variations.