The catch is if you are doing an MLM where the primary income is off of you buying products to use for yourself, in the long run it is very unlikely it will have a positive income result. If your primary income is from you getting back $20 to buy $100 in vitamins you wouldn't have bought and depending on your downline to do the same, run away. Then buy some cheap vitamins and smile knowing you just saved $75. If you really want to make it in one of those organizations brush up on your speaking skills, cross your fingers and be ready to invest like crazy, knowing you are nearly completely certain to fail. Everybody who joins is really into it, they all want it really bad, they all do all the steps and still the failure rates at any sort of meaningful success are often above 99%.
Then there are MLM companies where your primary business is to sell a product to other people and you have a product people would actually go to silly parties and buy. You can do ok with these if you are motivated and very social to begin with. You have to ask yourself, once all of my friends have already seen this, if I pretend they all said "no" to everything I sell, is there any realistic way for me to make money? Even if you do well with a product sales company, most people (most by a long stretch) earn less hour by hour than if you got a part time job and the job is usually less stress.
The people I have met in MLM who are successful are doing well because they are good motivational speakers and in most cases primarily because they are really good at lying about how successful they are. They then make money off of writing books and convincing you that if you buy their book it will make you rich. Bingo, they just tricked you and 10,000 of your friends into buying their book and often into pre-ordering multiple copies to "beat the rush" which is how next week when you see them they say "I've sold X copies! Everybody wants this knowledge!" Then the cycle repeats. I have seen people create their own websites with pretend awards just to give themselves credibility in the MLM world. There is one group out there whose leaders actually voted among themselves for the best motivational speakers and placed themselves up at the top, posted it online and reference it as proof that they are leaders in the motivational speaking field.
So to directly answer, no. Please as a PP said track your expenses and pay yourself back before you fund your trip. If you truly are making money I am happy for you.