I have been riding Fung Wah buses for years. Buses run every hour on the hour from like 6 AM until midnight, to and from Boston.
They leave NYC's Chinatown, and travel directly to Boston South Street terminal.
A round trip costs $30. I think it would cost more in gas alone at this point...so even if you have a car, this is cheap.
They have the same coach buses as greyhound or any other line, and share the terminal with all of them in Boston, but they do not connect to Port Authority in NY, only Chinatown.
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