As easy as it can seem to get started with paid placement, you will find that it takes some work to manage the bids in mulitple search engines for hundreds (sometimes thousands) of keywords. If you do not carefully monitor your campaign, you will find that you are being outbid (and losing traffic) or that you are paying more than you need to. Unfortunately, monitoring your bids can be labor-intestive, especially in hyperactive markets where others are constantly monitoring and adjusting their bids.

If you are willing to pay 45 cent and snag the top spot. Now you have the top spot, and you are paying well under your budgeted maximum. It is crifically important that you continue to monitor, however, because your competitor (or someone else) could bid 22 cent and you will loss the top spot. If you are monitoring, you can keep raising your bid to stay #1 until you hit your limit of 45 cent.
You might be able to remain at #1 withoout monitoring for quite a while if you just bid 45 cent right off the bat. But if the next bid is 20 cent, you are wasting 24 cent on each click, because you would get the same #1 position for 21 cent. That 24 cent is known as a bid gap. You want to eliminate bid gaps as soon as they appear - most paid placement engines do this for you automatically.

You need to monitor your bids frequently to make sure that you maintain your position, do not exceed your limit, and eliminate bid gaps as soon as they appear. Otherwise, you could use bid management software recommended by Google Adwords or Google Adwords Software.

Every paid placement program provides a way to automate your bidding. You can set "caps" for your bids (45 cent in your example), set intervals for how frequently your position is assessed, choose the rules for how bids are modified - all without having to personally check contantly. If you use only one paid placement program, you can use the free bid management tool that is part of the program (Google Adwords or any other adwords package comprises bid management tools). Hope today's blog post may help you in better findings.