Oh, you would put money into an isa first? Or just a standard savings account?
So Premium bonds aren't a great return compared to say a decent ISA savings account. But they are a bit of fun, unless you are me moaning about pitiful returns this year
The winnings are tax free, so depending on your tax rate you will win somewhere between 20% and 45% more than a taxed savings account.
My advice to anyone is this:
1. pay your mortgage off first - no point having money in the bank earning 3% when your mortgage is 5% or whatever
2. max your tax free investments (ISAs PBs)
3. only risk what you can afford to lose on the stock market
4. property investments are normally more work for less profit than 3, but most people understand how it works.
5. leverage your skills. if you can do up a house then buying a nice holiday let and renting it out having done it up can be fun.
someone will say leverage and gear you debt blah blah etc.. but for most people keeping it simple is best.