We've searched the internet and found the largest collection of On30 Scale trains for sale is on eBay. Below are the listings for 'Caboose'.

SPECTRUM 27199 ON30 Tank Car Black Painted Unlettered Bachmann
SPECTRUM 27199 ON30 Tank Car Black Painted Unlettered Bachmann
$49.95
Time Remaining: 8d 23h 22m
Buy It Now for only: $49.95
SPECTRUM 26314 ON30 Pennsylvania Coach PRR Bachmann
SPECTRUM 26314 ON30 Pennsylvania Coach PRR Bachmann
$39.95
Time Remaining: 8d 23h 27m
Buy It Now for only: $39.95
BUDWEISER  CABOOSE  HAWTHORNE VILLAGE NARROW GAUGE  On30 Scale Train MI
BUDWEISER CABOOSE HAWTHORNE VILLAGE NARROW GAUGE On30 Scale Train MI
$89.99
Time Remaining: 16d 6h 46m
Buy It Now for only: $89.99
COCA COLA  COKE CABOOSE  HAWTHORNE VILLAGE NARROW GAUGE  On30 Train MINT
COCA COLA COKE CABOOSE HAWTHORNE VILLAGE NARROW GAUGE On30 Train MINT
$99.99
Time Remaining: 16d 7h 56m
Buy It Now for only: $99.99
HON3 WESTSIDE LUMBER COMPANY CABOOSE LOGGING
HON3 WESTSIDE LUMBER COMPANY CABOOSE LOGGING
$65.00
Time Remaining: 18d 9h 45m
Buy It Now for only: $65.00

Other On30 Scale train items recently purchased through this site:

HON3 WESTSIDE LUMBER COMPANY CABOOSE LOGGING
BUDWEISER CABOOSE HAWTHORNE VILLAGE NARROW GAUGE On30 Scale Train MINT
COCA COLA COKE CABOOSE HAWTHORNE VILLAGE NARROW GAUGE On30 Train MINT
SPECTRUM 26314 ON30 Pennsylvania Coach PRR Bachmann
SPECTRUM 27199 ON30 Tank Car Black Painted Unlettered Bachmann