What a great "blue light special"!!!
I just bought more Wellesley (VWIAX), Total Stock Market Index (VTSAX), and FTSE All-World Ex-US (VFWIX).
I bought with funds from my VMMXX (Prime Money Market) account at 8:05 Eastern Time. I don't know if I got today's closing rate, though, since I bought at 8:05 PM Eastern Time. That might be too late. (?)
But then, the market might plunge more on Monday so it could be a good day for buying, too.
You will get the price as of Monday's close on your new purchases. To get the day's prices you have to buy before the market closes on that day (usually 4:00 pm ET).
I sold 1/3 of my bear market fund on Monday and used the proceeds to buy more VTSMX (total stock market index) and VGTSX (total Int'l stock index) today. I also used new money to buy more VEIEX (emerging markets) and NAESX (small cap index) today.