Tableau Server is often more affordable than providing Desktop licenses to all your dashboard developers. In addition to one Desktop license, Minimum of 10 users can publish reports. As per the list, price is $1000 per user license.
Price list by partner website putting each license online around $800. So a minimum investment would hover around $8-10,000.- presumably, plus whatever hardware you intend to run it on. Unlimited users on an 8-core server will set you back a cool $200k.