What is the best mutual fund to invest in with just a little money...like $100?

Look at the MSN.com "Money" page.Many good tips,articles,and links.
I think most mutual funds require a minimum initial deposit to open,and $100 is most likely well below that limit.
However there are funds that waive the minimum initial deposit if you enroll in an automatic monthly transfer plan.
Just read the fine print before you commit.Some of these funds have different fees and costs.Some of them charge a fee (or "load") to enroll (avoid these) and some charge a redemption (or "cash out") fee.Most funds charge a redemption fee if you try to cash out early.30 to 90 days is usually the norm.But stay away from funds that have an open-ended redemption fee,those being the funds that want to take a bite out of your kitty even if you wait 20 years to cash out!
You also want to read the prospectus for any fund before you invest.That's the booklet they provide that outlines the funds fees,holdings,and past performance figures (among other things).Pay special attention to the management fee.It is expressed in percentages.It tells you what percent of your fund they are going to pocket every year for doing business with them.You didn't think these people were working for free did you? This fee gets deducted NO MATTER how well (or poorly,for that matter) the fund is doing.Try to avoid funds that have management fees higher than 1%.Some funds charge more,but they are usually the better performing funds,and still might be worth looking at.
You have $100.Save another $25 and buy "Mutual Funds For Dummies". Great book.It'll give way more good information than you can get here on Yahoo Answers.
Good luck!

Investing in mutual fund is really a good idea.. Before investing learn more basics about it.. If you are first time investor means just go to the broker office & get the guide from them.we cannot predict the future in stock market .Just take a look at the below link to get free information regarding mutual fund.

I beleieve the minimum investment on a mutual fund or CD etc. the minimum investment is usually $5000. I dont think you are going to find anyone to do it with $100.

to invest that little in a mutual fund, you would probably have to agree to invest that amount regularly. which happens to be a great way to invest. go with the big ones with little or no fees. funds like fidelity, vanguard, etc.

I would maybe try Neurberger Berman AMT Balanced fund (NBABX) or Vantagepoint Growth (VPGRX).