Go for Ethereum as this cryptocurrency has high liquidity, usually ranked #2 or #3, right below the BTC, and also suits your budget. You will never have trouble to buy or sell this cryptocurrency. Also, it has a loyal community, thus its value has a high probability of staying stable and rising in the long run.
Volume or good liquidity is the most important if you are day trading, but you cannot expect that the same coin will always be volatile.
The market has billions of trading volume now, if you are trading with less than a million a day, you'll never find it hard to find a high volume coin to trade.
Some of these older coins now are really lacking volatility for trading because investors are more particular about investing in newer projects now, so if any trader is to really consider volatility or volume, I think new projects and very few of these top coins will do it, but not ripple.
I wonder how much ripple was when the op posted this topic, if he had invested or traded ripple then, I am sure that he will be full of regrets by now, while Bitcoin still remain the only coin that one can always guarantee its volatility for trading for the next 5 years, because time is also coming when Bitcoin will really not have any volatility again.