You should be able to find a decent lawyer somewhere that would do a simple will for a few hundred bucks. I'm not just saying this because I'm a lawyer (but now moving into teaching as a career) but doing your own legal documents to save a few bucks is about as smart as doing your own plastic surgery. The problem is you will have no idea whether or not the form you are using is in your best interest. The real problem is not whether you have inadvertently put together a document that is not sufficient or binding, but rather whether you have put together a document that is sufficient and binding but has unintended consequences.
Go ahead and ask legalzoom or nolo if they are liable for their work, you'll find they are not. If they aren't willing to be responsible for the quality of their product, should you be using it? Believe it or not, there is a reason lawyers have to go to law school. If you just use somebody's form, they cannot possibly have foreseen your unique circumstances. Just like other products, you get what you pay for.
In fact, I'd suggest these forms are way too expensive. When you retain a lawyer, you are purchasing his experience, specialized knowledge, and analysis of your needs. That should and does cost something. Why on earth should you be charged more than $5 for an online form? What are their expenses? A little server space? Maybe some advertising? Actually, part of what you're paying for are their defense fees, because neither legalzoom or nolo will tell you about how frequently they are defendants in lawsuits. Sadly, these are unsuccessful lawsuits, because your agreement with them will include language absolving them from any responsibility for the quality of their services.
As an example, I had a long-term client who owned a small home building company. For years, I told him he should have me review his contracts. He didn't want to pay me to do that, and insisted he had a great contract he got online.
Then he finally had a deal go bad. I defended him in the lawsuit. At trial, the judge asked him why he never had a lawyer review his contracts. The client said he didn't want to pay the legal fees. The judge told him he hoped the client had saved a lot of money, because even a poor lawyer would have seen how bad the contractual language was, and using the form contract was going to cost him $130,000 that day, because no legal talent or argument could get him out of the contract's clear but disadvantageous language. When my client asked about suing the online legal document site, I pointed out their language disclaiming any liability.
Like anything else, you get what you pay for, and sometimes less than you pay for. You won't know which until it is too late.