How far back can you go paying for the $350/month?Try QuantGo. It's "renting" data, where you pay for a monthly subscription and can only use the data on their servers (AWS machines) but their prices are very reasonable compared to the tens of thousands historical options data tends to cost from most vendors. Options TAQ is $350/month with a 6 month min plus a pretty reasonable per-hour fee for renting the cloud servers.
Reason I ask is brokerages normally provide up to 6 months of free historical option data.