Keyword bid pricing in Adwords are very subjected to the competitiveness of the keywords you are targeting. The more competitive the keyword is, the more you have to pay (assuming your quality score is average like 6 or 7, and new). You need to find the right bid price to market.
There are two types of bid price, one in Adgroup level and the other in keyword level.
Adgroup Bid Price
This is the where you set the default bid price in the Adgroup for the 100 keywords. The main primary function of the default bid price in the Adgroup is to make sure the keywords bid have at least a bid, in case if you forget to set it. Adwords are very systemically that when you create a new Adgroup, you MUST set a bid price for the Adgroup level. You can set the max price bid here for the Adgroup, but i would rather you not do this.
Here is a previous post which you should read as well.
=> Be Careful Of Your Adwords Bidding
Keyword Level Bid Price
It where you have to set the bid price accordingly to the keywords in the Adgroup.
Different keywords have different bid price, depending on 1) the position of the PPC ad you want, 2) the price you are willing to pay, 3) the quality score of the campaign, and lastly 4) the competitiveness of the keywords you are targeting.
If you have taken note of the four points above, your keyword bid price would be different from a new Adwords user and old experienced Adwords (with great quality score), if you want to bid for the same keyword. Yes it is true and I have tried it myself. The above four point are fundametal or a formula to Adwords PPC.
Take Home Advise for Keyword Bid Price
Test the keyword bid price by using the Ad Preview Tool, to view where your position of the Ad is. The Ad Preview Tool will tell you how much you will be paying if you want to be at a certain Ad position. You can always adjust the bid price of the keyword accordingly. Just a note, the Ad Preview Tool is 15 minutes delay, after you set the new keyword bid price. This is quite intensive for your info, but if you want to pay the right price, then this is the price you have to pay (physically).