So for reference it is nothing like a savage or yeti! And probably weighs about a quarter of either of them if not less!... (1.5/1.6 kg max)
They are designed specifically for rock crawling at slower more precise speeds. They'd break if you rock raced them....
However , if you fancy rock crawling then they are the best rigs period... With regards costs it of course depends on how you build them up.. For example:
1. The chassis and links - iirc they were around €150/200.
2. Then you need AR60 axles £50/£100
3. Then Overdrive front Ring and Pinion and under drive rear sets £60 ish new
4. Shapeway parts for axles and gearbox €200 ?
5. Gearbox gears from Pat €50? You could of course run a cheap axial 3 gear transmission - £20 for a china version..
6. Motor, Esc, Servo, RX - Spend what you like here! But ideally we want something light for the motor - Mine is a Holmes Hobby Crawlmaster Puller 400.
7. Wheels and tyres - Most common to find in the UK will be Proline Ibex or HPi white dot rovers.
So really it depends on what you have and what you wanna use but I'd guess at best it'd be around £500. Using even more bespoke parts you'd be around or above £1k. Cheapest way in is probably buying second hand - though you are unlikely to find many Ventrus but others do pop up on FB.
Hope that helps some.