6 year old has a very expensive wish list :)

[trainbrothers]

Can anyone else relate? My 6 year old son LOVES model trains and has been an avid train lover since he was 18 months old.  My problem is he is attracted to the most expensive sets.  Does anyone have advice or an explanation I can use to explain to him why model trains are so expensive? Any tips or guidance is much appreciated.
Sincerely,
A train supporting mom

[trainbrothers]

Here is his wish list to give you an idea:
- Amtrak City Sprinter
- Acela Set
- Amtrak Acela II Set
- Daylight Special
- Track King
- Coastliner
- Overland Limited
- Circus Spectacular