There is no such “Right” amount for Google AdWords. It depends on many factors like targeted keywords, audience, goal, CPC of the keywords.
WE would keep in mind the value of your customer/potential client. Use that # as a targeted ad spend for the week/month.
Example: if a mold cleanup company is running Adwords and his average job is about $5,000 then he would use that as a decent ballpark monthly budget. You can certainly break this down to daily, but AdWords takes time so you may be frustrated at first. Also, keep in mind that the more competitive the keyword is, the more you’ll have to pay for visibility. If the ROI isn’t there, you may need to rethink your strategy/ ad platform. (ex, for certain industries, paid social ads may yield better results)
Best thing to do is Determine a budget, or at least an amount they are willing to spend. Determining volumes and rough amounts (CPC) can be done (in part) by using the Adwords Tools section. The Adwords Tools will more or less tell you an expected range that you can spend, but you also have to realize the tool is only as specific as you tell it to be. Many times the volumes and CPCs are merely a loose representation of what should be spent, as it doesn’t always take into account your exact audience.
In the end, we advise our clients, determine a budget and let me build you a campaign to maximize your spend. For instance, I manage a $50k monthly spend for 1 client, but a $2000 spend for another. Both have different audiences, but in each case, I explain what good results are and where we can potentially improve.
Having said all this, spending anything less than $50/day is more or less a waste of resources; even for a very regional company. This is because with $50/day they simply won’t get the recognition (impressions or CTR) they want/expect and it’ll sour the experience for both you and Google Adwords.
At thinkcode, If you are looking for the cheap solution then we are not the right choice, but if you are looking for Best Solution which provides the return on investment, then we would love to help you.