How much $ to move the market?

what trade size does it take to trigger a market move, say 20 pips. i expect that it would take less during the lower liquidity sessions to push the market around.

20 pips over what timeframe? And in what pair? It makes a difference.

isn’t 20 pips still 20 pips in whatever timeframe?

A market can move 20 pips in a blink on a news item. That has nothing at all to do with trading size. It’s just the orders on one side of the market disappearing.

If you’re talking about something a little less instantaneous, that might take a couple minutes to work through the system, then you would need to see a bit of size.

If you’re talking about timeframes longer than a few minutes, you get in to the realm of normal volatility, which doesn’t necessarily having anything to do with the amount of actual trading going on. Actually, from that perspective prices will tend to stay near levels where a lot of volume has been done.