Input error checking, C programming

I am very new to programming and having troubles. This is the second program I have written, aside from "Hello World". I got to this point by looking at other examples of user input error handling and taking those sections and adapting then into my program, sadly not fully understanding how they work, so now I am stuck.

My goal for this program is to have the user be able to enter the amount an item costs, then the program will print to the screen the sales tax on that items and the total amount of the sale for each of the three locations in the float section.

However, if a user enters a cost of .99 or 1.25, the program sees it as an error, and loops back asking for a positive integer. This is what I need to fix, the user needs to be able to enter, the cost without cents such as 125 or with cents such as 124.95.

Please help

//Author: David E. Berry
//Date: 15 May 2009, 23:38 this works for only positive numbers
//Revision: 2.0.9
//
 
#include <stdio.h>
#include <stdlib.h>
 
 
int main(int argc, char *argv[])
 
{
 
char input[BUFSIZ], *p;
long iAmountofSale;     /* Used to for long result*/
 
 
 
//Section for Intro Text
   
  printf("\n\tKudler Fine Foods Sales Tax and Total Calculation Program\n");
  printf("\n\tversion 2.0  Author: David E. Berry\n");
  printf("=========================================================\n");
  printf("\Sales Tax per Store location and Sales Total for that location\n\n");
  
//Section for numbers to plug into equations
  
 
  float iDelMarTaxRate = 0.0725;
  float iEncinitasTaxRate = 0.075;
  float iLaJollaTaxRate = 0.0775;
  float iTax_Result_DelMar = 0;
  float iTax_Result_Encinitas = 0;
  float iTax_Result_LaJolla = 0;
  float iTotal_Result_DelMar = 0;
  float iTotal_Result_Encinitas = 0;
  float iTotal_Result_LaJolla = 0;
 
 
     printf("Enter purchase amount: $");
 
//Error handling section to ensure positive interger for input
 
     for(;;)
     {        /* Infinite "for" loop until the user enters a positive number */
 
		fgets(input , sizeof(input), stdin);
 
		iAmountofSale = strtol(input , &p, 10);
 
		if(input[0] != '\n' && iAmountofSale > 0 && (*p == '\n' || *p == '\0')) break;
		
		else printf("Invalid input!\n\nPlease enter a positive integer for the amount: $"); /*Displays if the user did not enter a postive number*/
 
		iAmountofSale = 0;
 
      }
					
      printf("\nYou've entered the amount: $%ld\n", iAmountofSale); /*Displays what the number user input correctly*/
 
 
//Section for tax equations and results
    
               iTax_Result_DelMar = iAmountofSale * iDelMarTaxRate;
               printf("\nSales Tax for Del Mar is $%.2f\n", iTax_Result_DelMar);
  
               iTax_Result_Encinitas = iAmountofSale * iEncinitasTaxRate;
               printf("\nSales Tax Encinitas is $%.2f\n", iTax_Result_Encinitas);
  
               iTax_Result_LaJolla = iAmountofSale * iLaJollaTaxRate;
               printf("\nSales Tax La Jolla is $%.2f\n\n", iTax_Result_LaJolla);
               
               
//Section for Total Amount of sale equation and results 
 
 
               iTotal_Result_DelMar = iAmountofSale + iTax_Result_DelMar;
               printf("\nTotal Sale for Del Mar is $%.2f\n\n", iTotal_Result_DelMar);
  
               iTotal_Result_Encinitas = iAmountofSale + iTax_Result_Encinitas;
               printf("Total Sale for Encinitas is $%.2f\n\n", iTotal_Result_Encinitas);
 
               iTotal_Result_LaJolla = iAmountofSale + iTax_Result_LaJolla;
               printf("Total Sale for La Jolla is $%.2f\n\n", iTotal_Result_LaJolla);
 
 
          
     
 
 
  system("PAUSE");
  
  
  return 0;
}

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