Yes these companies are legit, many of them will have different incentives for going to the presentation and when you get there they will try to hard sell you but if you stick to your guns and keep saying no then you can make it out with your gifts without spending anything. Just make sure you meet the requirements so they dont disqualify you. Those requirements are usually just being over 21, making at least 25,000/year and bring 2 forms of id (dl and checkbook/credit card) and if you are married or engaged your so usually has to be with you.