The current cost of a DAI transaction may be determined as a function of three variables:
- the gas price that you offer to pay
- the amount of gas used by a DAI contract call (which does not change)
- the current ETH/USD exchange rate
We then have:
(transaction cost) = (gas price in ETH) * (gas used) * (exchange rate)
By offering to pay more for gas, you can make your transaction faster. This page uses ETH Gas Station to determine a sensible gas price, which allows for transactions to complete in ~2 minutes.