Hi, I am a fresh graduate who is currently putting aside around $500-$800 for retirement/investment. Which brokerage should I use?

You'll probably save more on 0 commissions with TD Ameritrade than on IBKR buying Irish Domiciled ETFs... the tax on dividends on small AUM is really little

From what I know, Stashaway does not currently have a mechanism for transferring your holdings out to a third-party broker, which means that you will have to liquidate your holdings and transfer it out in cash. You may want to keep part of your holdings there if it aligns with your investing plan or philosophy.

Since you are investing between $500 and $800 monthly, Interactive Brokers may not be the best option for you. Interactive Brokers charges a monthly minimum commission of 10 USD. You may want to consider using Standard Chartered which does not have any recurring fees for buying Irish-domiciled ETFs, and investing in less frequent intervals in order to accrue less commission. In the future when you increase your investment amount and frequency, you can switch to Interactive Brokers where the savings on foreign currency exchange may outweigh the costs of the minimum commission.

Alternatively, you can directly invest into the US markets using TD Ameritrade, but keep in mind that dividends are taxed at a rate of 30% (vs 15% for Irish-domiciled ETFs) and possible estate tax obligations. The higher withholding tax rate may not matter as much if your investments are relatively small or pay little/no dividends.