I have transferred $16k last night to Etrade to purchase 40k of...

I have transferred $16k last night to Etrade to purchase 40k of SXY.

I have never traded any stock successfully, but for the time being I think whilst my business is quiet, perhaps
I can pick up a few bucks whilst it appears to go no where lately.

For you traders out there, I`m not asking your buy and sells prices......but what quantities do you guys consider
trading with.

Cannot get the money until tomorrow, but 37.5 would be a good start

thanks in advance if anybody wisheds to answer.