I read something somewhere that one should never invest more that 1% or 2% of one's income in the lottery because the chance of winning is so low.
Your reading sources, use the term invest in place of gambling expenditures? 
Well, I am going from memory, maybe the source said spend but I think in terms of investment. If you spend $20 a month on the lottery, it is money you could be investing for a sure return somewhere else. But I think it was a book on investing and the author I think was going over what some people consider financial plans. Some people will say "winning the lottery" is their financial plan and I believe the author was writing in terms of risk and reward and why winning the lottery was a poor financial plan. And that there are other things you could do with your money that would have a better chance of yeilding rewards.
It could have been one of the Rich Dad books or it could have been a book I bought on trading options.
There is extra pressure when it is an office pool, though, because you don't want to be the one left out if they win. So there is that to take into account. So really it comes down to how much it bothers you to put $5 on a virtually guarenteed not-a-sure-thing versus how much it will bother you if your co-workers win and you are left behind.
But it is still good to know how someone who has an understanding of money views the lottery. The more information a person has, the more and better choices one can make. If anybody really wants to be rich, the lottery probably isn't the way to do it. Or since there is a chance one could win, it is good to know how much money one should be willing to risk on that chance. Like if someone is going to buy shares of Apple, they should know how much the shares are worth, if they are over-valued or under-valued, what price they should get out of the trade if it is going well or what price they should cut their losses on. Depending on how much a person makes, $5 a week on the lottery could be just right or too much or too little.
