Bogleheads.org

I really would work towards allocating your retirement investing towards index funds and really focus on putting your investments towards the lowest cost options available. I would keep the investment allocation very simple with the following recommendations: His 401k: 25% S&P 500 index 25% Fide...

I would go ahead and invest the lump sum amount into several index funds and not worry about where the market is currently.
If your time horizon is at least 5 years or more, I would invest the money and not even worry about if the "timing" is right.

I would look into opening your account with Schwab. They have minimums of $100 on their index funds and expense ratios are
super low and extremely competitive.