What makes a "standard" raise depends on how well the economy is doing, how well your particular industry is doing, and how well your employer is doing. All these things change constantly, so anyone who says, "a good raise is 5%" or whatever number is being simplistic. Even if true when he said it, it won't necessarily be true next year, or this year in a different industry, etc.
The thing to do is to look for salary surveys that are reasonably current and applicable. If today, in your industry, the average annual raise is 3% -- again, just making up a number -- then that's what you should think of as "standard".
If you want a number, okay: In general, as a first-draft number, I look for a raise that's 2% or so above the current inflation rate. Yes, of course I'd LIKE to get a 20% raise every year, but that's not going to happen in real life. On the other hand if a company gives me raises that don't keep pace with inflation, than barring special circumstances I'm going to be looking for another job.
But there are all sorts of special circumstances. If the economy is in a depression and unemployment in my field is 50%, I'll probably figure I'm lucky to have a job at all and not be too worried about raises. If the economy is booming and all my friends are getting 10% and 20% raises, then I'll want that too.
As others have said, in the United States at least, the best way to get a pay raise is to change jobs. I think most American companies are absolutely stupid about this. They don't want to give current employees big raises, so they let them quit, and then hire replacements at a much higher salary than they were paying the guy they just drove to quit. And the replacement doesn't know the company and may have a lot to learn before he is fully productive. And then they congratulate themselves that they kept raises this year to only 3% -- even though total salaries paid went up by 10% because the new hires demanded higher salaries. They actively punish employees for staying with the company.
(Reminds me of an article I read in a business magazine by an executive of a cell phone company. He bemoaned the fact that in the cell phone industry it is very hard to keep customers: they are constantly switching to other vendors. And I thought, Duh, maybe it's because you offer big discounts for the first year or two, and after that you jack your prices up through the roof. You actively punish your customers for staying with you more than 2 years, and then you wonder why customers leave after 2 years.)
Oh, if you do change jobs: Absolutely do not buy a line of "we'll start you off with this lower salary but don't worry because you'll get a big raise in a year". When you're looking for a job, it's very easy to turn down a poor offer. Once you have taken a job, leaving to get another job is a big decision and a lot of work. So you have way more bargaining power on starting salary than on raises. And the company knows it and is trying to take advantage of it.
Also consider not just percentage increase but what you're making now versus what other people with similar experience are making. If people comparable to you are making $50k and you're making $30k, you're more likely to get a big raise than if you're already making $80k.
If the company says, "We just don't have the budget to give you a raise", the key question is, "Is that true?" If the company is tottering on the edge of bankruptcy and trying to cut costs everywhere, then even if they know you're a good and productive employee, they may really just not have the money to give you a good raise. But if business is booming, this could just be an excuse. It might be an excuse for "we're trying to bleed employees white so the CEO can get another million dollar bonus this year". Or it might be a euphemism for "you're really not a very useful employee and we're seriously thinking of firing you, no way we're going to give you a raise for the little bit of work you do when you bother to show up".
My final word: Be realistic. What matters isn't what you want or think you need, but what you are worth to the company, and what other people with similar skills are willing to work for. If you are doing work that brings in $20k per year for the company, there is no way they are going to pay you more than $20k for very long. You can go on and on about how expensive it is these days to pay the mortgage and pay medical bills and feed your 10 children and support your cocaine addiction, but none of that is relevant to what you are worth to the company. Likewise if there are millions of people out there who would love to have your job for $20k, if you demand a lot more than that they're going to fire you and hire one of them. Conversely, if you're bringing in $100k a year for the company, they'll be willing to pay you a substantial percentage of that.