again, are you going for maximum number of wins, maximize number of dollars won or going for big prizes?
that affects your ideal strategy the most (again keeping in mind that in term of net money, statistically you certainly lose)
if you are looking at total money 'earned', than you need to calculate the statistical average of your return of investment per dollar spent.
if you get 5 dollars back on the $5 dollar tickets or 20$ back on the 20$ ticket, then it's the same, but what are respective odds of winning that specific prize? that will tell you which one is more advantageous. and you have to get that for all the prizes, including the middle ones (not sure if the odds per each prize are available)
Well I calculate the odds per each prize. For example, here's a document I drew up last week:
$20 ticket - 1 in 11.72 odds of winning $50 or more.
$10 ticket - 1 in 22.92 odds of winning $50 or more.
$5 ticket - 1 in 41.03 odds of winning $50 or more.
Odds of winning $50 or more are equivalent between these three tickets, relative to the price of the ticket.
$20 ticket - 1 in 22.92 odds of winning $100 or more.
$10 ticket - 1 in 42.76 odds of winning $100 or more.
$5 ticket - 1 in 983 odds of winning $100 or more.
Odds of winning $100 or more kicks $5 tickets out of the race. Even four $5 tickets doesn't come close to the odds you have of winning $100 with a $20 or two $10 tickets.
$20 ticket - 1 in 278 odds of winning $200 or more.
$10 ticket - 1 in 1,300 odds of winning $200 or more.
Odds of winning $200 or more now kicks $10 tickets out of the race as well, leaving the $20 ticket as the only one that gives you any reasonable chance of winning a decent prize.
But then at the same time, you have a greater chance of getting some of your money back with four $5 tickets vs. one $20.