Contrary to what many so called experts say, you need to practice with a crossbow . Just sighting it in and going hunting is a big mistake! Distance to shoot while hunting is about the same as a vertical bow. Most good, ethical crossbow hunter limit their shots to under 30yds. The short crossbow arrow has a rainbow trajectory and losses speed fairly quick even though there are some crossbows that shoot an arrow 380fps.
There are several very good crossbow manufacturing companies, with lifetime warranty and excellent customer service. The top two being TenPoint and Excalibur. Bowtec makes a couple of super fast crossbows and Horton makes a decent crossbow.
The adage that "you get what you pay for" holds true to crossbows! If you buy cheap, that's what you get!