Hi SF
TD Ameritrade has 100 ETFs that you can trade for free at most monthly. I am sure you can find enough AIM candidates from among them. It makes no sense to trade less than $500. I would combine accounts and have fewer, larger positions, even if that was one S+P 500 fund and one bond fund to start. I would not start any accounts with less than $20,000, half in stock and half in cash.
On something like MORL or MORT the dividend creates a large pressure to keep the price down. You might want to reduce the PC by 1/2 the dividend amount to reduce buying if you find yourself buying too much. Alternately you can do what I do with my Low Down Aim accounts where I increase the BUY SAFE by 5% with consecutive BUYS and reset when I have a SELL.
If the dividends keep up with the buying, maybe you do no adjustments.
I own REM at the present time And I think I decided I like MORL better than MORT. I may buy MORL when mortgage REITS crash.
Toofuzzy
Take the road less traveled. It will make all the difference.