This is the million-dollar question, and if that’s within your budget, I say spend it; sorry I mean pounds too (I have to cover both currencies now). There is no limit on ad spend and there is no minimum either (even though I wouldn’t suggest anything less than $1 a day); no matter what you’re spending, Google is like a greedy person who constantly wants more money, and who will constantly tell you to increase your budget; they’re a business so of course they will. You can tell them no though.
I have clients who spend as little as £4 a day to clients who spend £3k a day; there is no right or wrong answer. If your budget is on the slightly smaller scale then it just means you have to use your budget wisely. The management is still the same, but you have to be careful because with a smaller budget and a lot of keywords that budget will be gone in a matter of hours.
The thing you have to take into consideration with Google PPC is not only the budget you’re going to be spending on ads but also the cost of the company and/or person creating and managing the ads. These prices for management can be anywhere from an hourly rate of £35/$35 upwards or some agencies will charge you a percentage of your ad spend. So, if you’re spending $1000 a month on ads then they may charge you up to 20% of that for their fees. This is just an example, some agencies may charge more etc. It’s just always good to know that your budget doesn’t just stop at your ad spend.
You can start an AdWords account here if you don’t have one already; or I can do that for you, or if you do already have one, I can be added to your admins so I can manage it from there. If you would like to discuss with me what you think or feel or even want your ad spend to be, then you’re more than welcome to reach out. I’ll advise you on what your ad spend should be within your desired budget, what you should expect from that amount of ad spend and I’ll tell you how I’d manage it too.