I've got a stable setup:

  ---------------------------------------
  Vultr ========================== Linode
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  Los Angeles ==================== Dallas
  Mastercard 1234 ============= Visa 4567
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  VMs with custom Linux (ROOT/ZFS Debian)
  Replicating snapshots every 5 minutes
  CloudFlare + HAProxy Load Balancing

Total cost: 6 VMS at $20 each: $120, CloudFlare $20

Edit: backups to B2 and Wasabi. ~$10 month