I did Brokerage Link for a while (looks similar), and ended up moving everything back to my standard 403b because we have good index choices. Fidelity has a lot of low cost, no transaction fee funds you could choose, particularly FSTVX, which is their VTSAX equivalent. I don't know about your particular case, but with mine, I could direct a portion (or all) of my contributions and matching into the brokerage account the same as if I were choosing a fund. The money gets deposited to the core position, and you can either set up automatic investments, or do it manually. Obviously, YMMV, but with my account, there were no additional fees for using the BrokerageLink option.