If you have a Prusa i3 MK2 or later, since April this year the latest drivers/firmware were released that allowed for linear advance. What does this mean? It’s an algorithm that allows you print faster with the same and/or better quality that slower prints. Okay, that’s a bit overly simplified, but if you’d like to read more I’d go to this article by Matt Harrison.
Here is an example below. I printed this at 90mm/s and this was before I cleaned up the supports. This is Ziro Marble PLA I purchased from Amazon for $22 for a 1kg spool. Pretty good price and the print turned out great!