My favorite eZip, at the moment is a 2008 Trailz.
Bought it 5 years ago for about $250.
Sold the battery pack and charger, to a neighbor, for $110 and his old pack.
Added the 16T mod ... about $20.
Recycled a pile of old laptop batteries and the "old pack" into a 25.9V 31.2Ah pack. - About $30.
Run it about 5500 miles so far, cruises at 20mph with some assist to 25mph.
Good for ~50 miles@16MPH - motor only! (range trial)
+30 miles @ 20 mph with some assist - more typical. I have reduced peak charge voltage and raised minimum discharge voltage.

So, for ...
$250 - 110 + 20 + 30 = $190 I have a durable eBike that outspecs and outperforms almost everything on the market.

OK! ... it did require work, ingenuity and thought ... but well worth it ... IMHO! Now that I have trailblazed materials and methods, my upgrades take mere minutes ... recycled battery build does require an extended period of occasional observation - testing components.

Oh ... modified Meanwell power supplies into a 5 and 10Ah quick charger.
About 3 hours for a +90% charge. - Total cost? About $10.
Possible to reduce that time to 1 hour, but 2-3 hour is probably better for best battery durability-lifespan.