Thanks for the replies. I think the answer is, if I have at least $25k in my account and have margins enabled, I can mostly do whatever I want but I'll have to pay a fee for the use of that margin.
If I don't have margin, then I have to pay attention to the 2 day settlement rule... I can buy on Monday up to 100% of my funds and sell on Monday as well. I can even buy on Tuesday, but I believe if I sell on Tuesday instead of waiting until Wednesday when my Monday transactions have settled then I'll be in violation of the free ride rule and could have my account flagged. Does that sound correct?
Let me add to this. Today, I was flagged on merrill edge for 'freeriding'. I'm not sure where the glitch happened. I make dozens of trades everyday as I am lucky to have $25k+ in the IRA. The page shows "cash available to invest", cash available to withdraw, and pending settlements, etc. I always use up almost all the cash avail to invest. If I want I sell a few things, or cancel some buy limit orders, then my available cash to trade instantly goes up that amount. I buy with that thru the day. I thought I got in trouble today because it was the same security, IYK, that had a stock split that confused me the night before. Tho, other examples of freeriding use ABC stock and XYZ stock, tho there must be a "buy ABC, Sell ABC, buy XYZ" pattern to this also. I could swear I have bought and sold many holdings the same day, with unsettled funds, and I do not have a margin account. Tho it is rare I buy and sell the same holding in the same day, and there is a wild price swing (rare), and I have only unsettled cash. that is why I was so surprised today. And they expect you to depost a whopping $251 cash to cover the sale, even tho I have $1500 now settled cash available, They want NEW money. Its, an IRA, I am trying to withdraw cash, not add cash.