New Haven, CT to Boston, MA buses and trains from $18

Or, see buses and trains from Boston, MA to New Haven, CT.
Here are some trips other travelers have found on Routefriend.
$18
3h 35m
0 stops
Peter Pan
$18
3h 5m
0 stops
Greyhound
$24
4h 45m
1 stop
Peter Pan
$39
2h 3m
0 stops
Amtrak
$24
3h 10m
1 stop
Amtrak Peter Pan
$31
6h 12m
2 stops
Peter Pan Amtrak
$36
3h 55m
1 stop
Greyhound Amtrak
$44
7h 23m
2 stops
Amtrak Greyhound
$45
8h 3m
2 stops
Amtrak Peter Pan
$45
7h 23m
2 stops
Amtrak Greyhound