I wouldn't do it. Some of those coins are cheap for a reason, i.e., no one wants them. You have to look at whether there are any buy orders on the exchange you're looking at, what the trading volume is, etc. It could easily happen that once you buy one of those coins you'll never be able to sell it. Some of them are moribund and will never rise above 1 cent or 1 satoshi ever again.
On the other hand if you've got money to play with and can stand losing it, go for it. You might get lucky, but I'm thinking you probably won't.
I'd buy no more than a dollar's worth of each coin to start with
Now even though I just said it's probably not worth it to buy any of these turds, I would say that IF you're going to do it you ought to buy more than $1 worth. I'd probably buy $10 at least, but that's just me. A coin would have to seriously skyrocket to make $1 turn into anything significant. There are exchange fees to consider, and trading minimums too. I'm not even sure if $10 would be too little for most exchanges.