If you're new to oil, I'd look at getting on a budget plan, then you pay monthly into an account and draw it down over the year to avoid the spikes. Prices are high across all types of energy due to Russia unfortunately but are lower than they have been over the past few months.

If you want to nerd out on the data, this is the wholesale price for heating oil over time.

Most homes in the northeast use between 500-700 gallons per year. During cold snaps/peak winter months it's not uncommon to use 100-150+ gallons in a month for a 1500-2000/sqft house.

All this depends on insulation, how you set your thermostat, etc ymmv

Source: I work for an oil company