I hope that you will take this advice in the helpful tone that it is meant, but… you know nothing about investing, and “looking around the web for investment ideas” in that state of ignorance (hey, we were all ignorant once; it’s not an insult and not meant that way) will part you from your money, and quickly.
You’ve gotten good advice above, to a point:
1. Primerica is a (mostly) legitimate insurance company and vendor of financial products and services. It’s true that their marketing scheme is “multi-level marketing”, which can be a big problem for the unwary. It can work very well for the right kind of person… who doesn’t mind trapping the unwary.
2. They don’t own the Rule of 72. Basically, as @zenvelo notes, the Rule of 72 is a simple mathematical formula that determines at what rate your money will double, given various rates of return. Primerica points that out, because one of their tenets – and this is a good one – is to buy term life insurance and “invest the difference” (that is, the difference between the lower cost of term life insurance and the much higher cost of “whole life”, which includes a growing cash value component). In general I agree with Primerica here that whole life is a bad buy for most people.
3. At some point in your life, if you follow the “buy term and invest the difference” philosophy wisely and well, your investment portfolio will have grown to a point where high-value life insurance to protect an income stream for your family will be obviated, because the portfolio itself will be more than equivalent to your insurance needs. But that takes a discipline that many people lack. That is, the discipline to “invest the difference” year after year and to manage the investment “wisely and well” – and to avoid tapping it when it’s right there and so convenient and you want something you can buy with it so much. Etc.
Before I would buy into a scheme where I could buy a cargo container for $5000 and earn a guaranteed return on it, I’d want to know ALL of the details, including who was going to be doing the paying, on what basis and in what form, and what are all of the assumptions about usage rates, insurance, demurrage (Do you know what demurrage is? If you don’t, then this isn’t a good idea for you to even consider yet.) and other things that I’ve never considered – but only because I’ve never been exposed to this “investment”. It has the potential to be rewarding based on the little bit that you’ve said but that depends entirely on the details of the proposition and the reputation and trustworthiness of the one making the promises.
Your best bet is to search the web (or a local library) to “learn about investing”. You need to understand concepts and some general rules about investing before you plunge into any specific investment – even the generally good advice that @LostInParadise offered.
Finally, when you know about investments in general, then you’ll realize the wisdom of @janbb‘s advice, too: “promised regular annual returns” of > 10% are either highly speculative, come with more caveats than you can count – or are outright lies.