Fund Broker Buying Vanguard Mutual Fund Through Vanguard Or A Broker?

Buying Vanguard mutual fund through Vanguard or a Broker? - fund broker

I thought the purchase of shares in a pension fund for the Vanguard mutual 2055th However, there is an initial deposit of at least $ 3000 to start a fund.

Is this even less if I bought shares in the fund through an intermediary Trade King cost allows me to acquire the funds and shares? Whether these funds will be available through them?

If so, it would make sense to buy through them and connected to avoid the costs associated with the avant-garde?