Pennies are more or less worthless monetary objects. It's gotten to the point where they can not buy anything remotely useful with a small amount of them. Nickels are suspect also, but I'll let that be for now. It is my claim that pennies waste time, resources, and money that could be better used in other ways and provide practically nothing.
Practically any transaction in America today is going to require that you give a few pennies to someone or receive a few. It will probably be less than 5 but this isn't the point. The point is someone is going to have to give you "exact change" to make sure you aren't jilted out of 57 seconds worth of a minimum wage workers earning potential. This might only add 10 seconds to the transaction. It might also add 60 seconds, to open a new roll of pennies, to search for a few linty pennies in your pocket, to politely explain that you don't mind having your change rounded to the nearest nickel, in the shops favor. There is also some cost associated with designing, minting, distributing, collecting, counting, etc of pennies. It might even cost more to maintain them than they are worth.
Pennies provide the ability for shopkeepers to charge $4.99 for something. This is of no advantage to anyone but the store owner. The store owner sees $5, the buyer sees $4. It's a mild misleading circumstance that most people are aware of, nonetheless it works. The convenience of paying exactly $5 is enough that I would forgo saving the extra $0.01. The ability to just slap a 5 spot on the table and leave is quite tempting.
Ah, but what about tax! If we have no pennies, we'll be constantly getting cheated on every transaction. After all, 8.25% of $5 is $0.41 which will probably get rounded to $0.45 in the shop keeps favor. I might be inclined to say, "so what", since this makes the effective tax rate 9% instead of 8.25% on a $5 purchase, but on a $50 purchase there would be no difference. Again, at most you'd lose 4 cents. But, never fear anyway, for I have the solution! The shop keep should figure the tax into the price listed! In other words, what you see is what you pay. If you want to figure your bill in your head, it will require no estimating, and no mental tax calculation. I'd actually pay in cash again: I would know FOR SURE whether I had enough, and the convenience of having the credit card company do the calculations wouldn't be so great (because even I could do the new money math). It would go like this: instead of thinking of tax as something the consumer adds on to the price, think of it as something the store owner subtracts from his sales. That way, the shop owner pays a flat percentage of his daily sales, and no other calculations have to be done. So for the fictitious $5 item, he has a choice. He can charge $5 for it and swallow the loss. This would make the "actual" cost of the item $4.61, the rest would go to uncle sam. He probably wouldn't do this. Instead he would probably charge $5.50 for it. Either way, you know exactly what you're getting for it up front.
This makes the store manager work marginally harder. However, he's doing it for profit, and should logically be the one to assume some work for his profit. Also, it is far more logical for a few people to do a little extra work than for a large group (the consumers) to do it. Also, the shop owner will be doing it in large scale, so it will be familiar, and possibly even automated for him.
As an aside, a similar scheme should apply to restaurants. A minimal tip should be figured into the bill, that adds to the waiters salary or goes into a waiters top pool. I agree that sometimes service is so poor that no tip is warranted. However, it is NOT acceptable to be able to under pay without lodging a complaint, which is what refusing to pay is (you essentially walk out without paying the waiter, without telling him why, without complaining to the manager, etc). If you feel it was really lousy, you can ask the manager to remove the "mandatory" tip. This is the same thing you would do if you bought something defective. You wouldn't just walk in and get a new one and walk out without asking would you? Of course not. If you think the service was good, you can leave a little extra. Of course I wouldn't reject the idea of eliminating tips from everyday life and replacing them with real salaries for waitresses. Again, if you really like the service, feel free to tip.
If the above financial policies interest you (namely abolishing the penny and requiring sales tax to be part of the price) you may wonder what you can do? Largely, nothing. Talking about it helps, since it's something that many people agree with when they think about it. Personally, I never pay with pennies, and am keeping every penny I come across. There is currently a penny shortage in the US. People are keeping them in jars, throwing them away, etc. I think this is great! If they become too much trouble they will simply be thrown out. Plus, what's cooler than having $500 worth of pennies?
Maybe so... But I recently took a trip to the middle east where what I've talked about is marginally common. Israel, for example, has tiny coins like pennies (or even smaller) but they are hardly EVER used. Most items are rounded to the nearest shekel (about 25 cents) and tax is included in the price. Tax is also a hefty 21%, unless you are not a citizen or pay in US$. Egypt has some ridiculously small bills (10 piastres, worth about 4 cents) but they are never used. I had to ask a bank for one! Instead, most things are rounded to the nearest 1/2 pound, about 15 cents. Taxes are included in the price. We can take a lesson from people like this. Maybe it will just happen on it's own.