Router with separate interfaces

Hi,

We have three separate subnets in our premises and I need some internal
services available to all three subnets. Does it exist a budget router with
separate LAN interfaces where I can connect my server to its WAN port and
our three subnets to its LAN interfaces while keeping the three subnets
disconnected from each other. Something like having a computer with one WAN
NIC and three separate LAN NICs.

Thanks for hints and comments on this

Geir