Slomo with Vegas is very easy. Put a clip on the timeline, press Ctrl and click your mouse on the right edge of the clip. Then drag it to the right to increase the length which slows it down. You can also drag it to the left if you want to speed it up.
If you need more drastic slomo than you can get from Ctrl-dragging, then you can apply a velocity envelope to the clip (right-click on the clip to see the sub-menu that includes apply envelope). This allows you to slow it down to zero and even reverse the motion. And you can also use it to ramp the speed from fast to slow or vice versa.