not addressing o_e_L_e_o, just using his comment as reference and addressing the other readers
DCA (dollar cost average aka constant dollar plan) is meant to be if you want to invest say $52k a year. instead of saving up $52k and then making one purchase at year end. you would under DCA save up $1k a week and just buy as soon as you deposit.
where by the 52nd week you should have a average of the years price. and not missed any opportunity during the year waiting to save up a lump sum.
but if you are like O_E_L_E_O who is worried about a $2.99 charge on $200 (1.5%) but not so concerned about the 5% swings of market volatility in a weeks period. then its not really 'reducing risk'
far better to deposit your weekly/monthly amount. and then look at the chart to see if when depositing if the price is at a weekly high or low. and buy if its at a low. or wait a few hours, days to buy the microdips that happen daily/weekly.
having a 'just throw the whole $1k at whatever price it is as soon as your deposit arrives". can cost you more then 1.5%, rather then waiting a few hours or days that week to take a better price.
very worse case you just buy before the end of week. still fulfilling your "just throw $1k at whatever price" mindset. and try again next week. to do better then "whatever price" mindset.
after all if your willing to buy at "whatever the price is" for the week. your not losing anything by still having that mindset if there was no dips during the week. but most of the times.. there are, so might as well try maximising the average by buying the dips
also. if an exchange does have a $200 order with $2.99 fee, but a $201 has a 0.5% fee($1) might aswell pay an extra 1cent on the order and save $1.99 on the fee.. you know common sense