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

Set of 3 Bachmann Spectrum 0n30 DRG  W Train Passenger Baggage Combine Cars
Set of 3 Bachmann Spectrum 0n30 DRG W Train Passenger Baggage Combine Cars
$149.99
Time Remaining: 3d 22h 20m
Buy It Now for only: $149.99
Coca Cola Hawthorne Village Baggage Car
Coca Cola Hawthorne Village Baggage Car
$80.00
Time Remaining: 16d 3h 50m
Buy It Now for only: $80.00
Railway Post Office Baggage Car Tokaido Sanyo 6 Car Set Model Train by
Railway Post Office Baggage Car Tokaido Sanyo 6 Car Set Model Train by
$178.49
Time Remaining: 19d 10h 45m
Buy It Now for only: $178.49
On3 On30 WISEMAN SM 101 DRGW OPEN PLATFORM BAGGAGE PASSENGER CAR KIT
On3 On30 WISEMAN SM 101 DRGW OPEN PLATFORM BAGGAGE PASSENGER CAR KIT
$89.95
Time Remaining: 25d 9h 45m
Buy It Now for only: $89.95

Other On30 Scale train items recently purchased through this site:

Coca Cola Hawthorne Village Baggage Car
Railway Post Office Baggage Car Tokaido Sanyo 6 Car Set Model Train by
Set of 3 Bachmann Spectrum 0n30 DRG W Train Passenger Baggage Combine Cars
On3 On30 WISEMAN SM 101 DRGW OPEN PLATFORM BAGGAGE PASSENGER CAR KIT