Uh, hate to burst your bubble, but you can easily buy any M44-series vehicles for less than $5k, and if fully restored, you can still find some for under $9k.
The M35 (A1, A2, A2C, etc) model is a nice vehicle if you wanna get started in the MV collecting hobby. For a basic setup that you want to restore yourself, you can get one for around $1000, and for a fully functional one (restored or not) can start at around $4k and up.
Yeah, tanks and rare vehicle models are hard to find and very expensive, but many and most are usually within the $2k-9k range for basic equipment.
Another nice model is the M37-series and the M181-series trucks.
Although a tank would ne nice to have as well... no space here tho. lol