GLBP equivalent / non-cisco proprietary protocol

I'm working on a project and I was wondering if I could find routers with a non-proprietary protocol which work like GLBP.

Here is the diagram.

I understand that now most of the routers come with VRRP but I've had hard times finding routers that have VRRP and load balancing services.

I'm looking for any idea which would avoid the excessive Cisco pricing.

EDIT R1 and R2 are gateways