OT: Personal finance experts, what are costs associated with "sale of fund shares"

[echappist]

One of my personal finance goals is to contribute to Roth IRA while I still can. While exploring fund options, I come across "return after taxes and sale of fund shares." The former I understand, and will be a moot point on a Roth IRA. The latter, I'm not sure why there would be such a significant difference (~0.75% annualized). What additional expenses goes into the actual sale of the shares, and why does it cost so much money?

Also, a corollary to this would be what happens when I rebalance my account (say by selling a large cap ETF and purchasing some long term treasury ETF), am I taking a hit on the "sale of fund shares" aspect when I rebalance? I assume this is not applicable to purchase and sale of stock shares as part of a Roth IRA, correct? Lastly, anyone got recommendation on readings for investing for Roth IRA and making additional investments when Roth is no longer an option (already maxing out 401k)

Many thanks in advance