I have a buddy I work with on the weekends that did that just. Got himself a mail order bride. She has treated him great. HE is the one that cheated on her "after" she got her papers. (dumbass) He was a total nut job. He was also back and forth in the service. And met a another chic in Germany. Brought her back here and everything. Total looser! BUT my point is she (latin chic) treated him well. The myth about how they marry you and dump you later is just that. A myth! The laws in the united states have gotten so stringent that once you get married you (the new citizen) must remain in the U.S. for minimum of 5-8 years, stay out of legal trouble for 5-8 years, must live in the same house or residence with your spouse for 5-8 years (and your office case worker can and will show up at anytime of the day or night to check on you) and so on. And at any given time the newly wed can be deported for any illegal reason. There are so many new laws in place to stop the marry and divorce for money types of people out there.
Most of the women you'll see on those websites are really hoping to get out of their countries and make a better life for themselves. Also remember, just cause they are up for sale (marriage) doesn't mean they WILL marry you. Many of these women still have their dignity and there must be some connection between you two. Most guys meet and date several women (in their country) before they find the perfect match.
If you are going to go down this road, find a place that has social gatherings once or twice a month. Meaning, these agencies have a meet and greet night. You fly over to where they live. All the girls come to a local restaurant or club that has been specifically closed for this affair. And it would be you and a bunch of other guys from around the world getting to talk, dance, flirt with the women on their website. Gives you a better insight into the women of your choice. Good luck brother.