Is there a difference in buying coins with bitcoin or etherum? So today I decided to throw my hat into the ring and bought some stellar lumen coins.  Since bittrex is not currently accepting new accounts I decided to go with poloniex. 

Poloniex doesnt offer lumen in their etherum market so I had to buy it with bitcoin, is there a difference when buying (any currency/token) with bitcoin or etherum?

I am still very new to the Cryptocurrency scene so any information would be greatful
The only difference could be with rounding depending on precision of coins with relation to value to each other. I think most exchanges are governed by law to not steal fractions of pennies but it's always an uncertain point sometimes and so I can not say you aren't in some cases losing fractions of coins. 

Also some times on inefficient markets crypto currencies may differ in prices across different currencies. This is an opportunity for arbitrage and typically doesn't exist. This may be caused by sudden changes in the market and usually temporary barriers. Like for example etc goes up rapidly, and LTC had been struggling, there may be a shortage of LTC and so there might be a temporary profit margin through LTC to etc then to btc. But usually the market players will balance things out quickly. It basically the speed of crypto currencies type thing like a ripple in a pond and probably a better topic for forex trading on economics or finance se. 

from a math point of view crypto currencies maybe analyzed with linear algebra where your portfolio is a coordinates of vector and basis is the currency to base currency exchange rate. Then redistributing the portfolio amounts to a linear transformation.