As others have pointed out market cap is typically more important than actual price per unit/coin.
Volume of trade also seems to have an effect, because the smaller the total volume of trade happening day to day the less likely a given trading-pair is to attract the attention of large players.
Thus if part of your motivation or intention of using the term "cheap" is that you do not have a large "volume" of capital to play with, it might be worth your while playing in low volume trading-pairs.
In essence, low volume pairs seem much more likely to be much more "inefficient" markets, presumably partly because professional "arbitrageurs" seem to consider them to be "beneath their notice".
That means a small player willing to make small absolute amounts of profit per trade by trading at small scales can find lots of small scale "arbitrage" opportunities that richer folk might even consider to be too much work for too-small lump sums of profit per trade.
Compare for example
BTC/IXC on FreiExchange to
XLM/IXC on Stellar; not only does the relative volatity of BTC versus XLM change things as it changes but also underlying that variance there is a fundamental inefficiency that seems maybe to mostly derive from the users of IXC on Stellar being skewed toward actual players of the
Galactic Milieu whereas the players of FreiExchange markets seem maybe more skewed toward pure crypto-markets players who maybe don't even have any awareness that the Milieu even exists let along that IXC is part of it.
The thing is, players in the Milieu route through Stellar to cash out their earnings toward whatever fiat currencies they are interested in, whereas people who tend to work with actual IXC coins on IXC's own blockchain maybe prefer to cash out via BiTCoin thus at present by using FreiExchange rather than Stellar to trade them on.
The same thing applies to
XLM/I0C on Stellar as compared to
BTC/I0C on FreiExchange, where you can probably also notice the correlation of low volume to high inefficiency - as I write this post I0C is even more out of synch price-wise between these two venues than IXC is.
So if you are a small player, you might find a lucrative niche for yourself in doing arbitrage between low volume trading-pairs, which is to say, buying things on venues where they are cheap and selling them on venues where they fetch a sometimes surprisingly higher price.
The larger the volume of trade the more arbitrageurs, and the more professional, fast, and well equipped with opportunity-finding tools, tend to "work" the pair, so as you grow in scale you will likely run into more and more-competetive competition but maybe spreading out over many low volume pairs could be a way worth considering of scaling up rather than moving to larger pairs where competition is more stringent.
-MarkM-