Aperture
Telescopes 10 inches (254 mm) and up gather enough light to show structure in galaxies and to break globular clusters into stars, especially under dark skies. They are heavy and bulky. A big SCT needs a heavy mount, and a big Dobsonian may need a trolley and a large car. Many end up on a pier or stay in a garage or shed between nights out. Used, plan the pickup before you buy, because a lot of these are sold locally or need freight shipping.
10 models we cover.
Celestron
Schmidt-Cassegrain$2,675–$3,600 typical ask
9 on eBay
Celestron
Schmidt-Cassegrain$3,625–$3,650 typical ask
1 on eBay
Meade
Schmidt-Cassegrain$2,750–$3,275 typical ask
12 on eBay
Meade
Schmidt-Cassegrain$2,100–$2,375 typical ask
2 on eBay

Orion
Dobsonian$850–$850 typical ask
2 on eBay
Orion
DobsonianSpecs and what to check →
Orion
DobsonianSpecs and what to check →
Sky-Watcher
DobsonianSpecs and what to check →
Sky-Watcher
DobsonianSpecs and what to check →
Sky-Watcher
DobsonianSpecs and what to check →