You can Normal Summon/Set this card without Tributing, but its original ATK becomes 1900. You can Tribute 3 monsters to Tribute Summon (but not Set) this card. If Summoned this way: Destroy all cards your opponent controls.
After Normal Summoning Beast King Barbaros with no tribute, you can bring him to full power by negating his effect. Axe of Fools can negate his effect while adding an additional 1000 attack. Forbidden Chalice is a great tech option and can be used on Beast King Barbaros to negate his effect.
In case you want to use Beast King Barbaros’ field wipe effect here are some cards that can help. Trojan Horse and The First Monarch can be treated as 2 tributes reducing the overall cost of summoning Beast King Barbaros. Obedience Schooled can Special Summon monsters from your deck to use as tribute fodder.
I’m going to try using this card in a fabled deck. It’s really easy to special summon enough monsters in one turn to get this card on the field and then to OTK your opponent using any other monster with higher than 1000 attack (assuming you go second).