Sam is in the Weigh the evidence stage of the decision making process.
Explanation:
In order to understand the answer to the question above we have to know what decision making is and the  processes involved.
Decision Making:
According to University of Massachusetts
Decision making is the process of making choices by identifying a decision, gathering information, and assessing alternative resolutions.
Decision Making Process:
Step 1: Identify the decision:
This step is very important, at this stage you realize that you need to make a decision and you understand the nature of decision you need to make based on the need to be meet .In the case of Sam this is the stage where he realizes that he need to make a decision to buy a new laptop
Step 2: Gather relevant information:
This is the step that involves the decision maker collecting important information before he makes the decision this entails him knowing what information is needed, the best sources of information, and how to get it.This step involves both internal and external “work.” Some information is internal: you’ll seek it through a process of self-assessment. Other information is external: you’ll find it online, in books, from other people, and from other sources.
Step 3: Identify the alternatives:
As the decision maker gains more information he/she would begin to gain insight and be able to identify several alternatives. the internal work in step two can lead to use of imagination and additional information to construct new alternatives.In this step, you will list all possible and desirable alternatives, and for our case study Sam this is the step where he narrowed the number of computers down to three.
Step 4: Weigh the evidence:
This is the stage where the decision maker involves his emotions and gathered information to foresee what it would be like if he/she carries out each of the alternatives to the end.Here evaluation is carried out to determine whether the need identified in step 1 would be meet or resolved through the use of each alternatives.As these  step is been carried out the decision maker begins to favor certain alternatives:those that seem to favor higher potential for reaching the goal. Finally the alternatives are placed in a priority order,based upon the decision maker value system
Step 5: Choose among alternatives:
Now that the alternatives have been place in order of priority this step then entails the decision maker selecting from the one that seem best to him. He may even choose a combination of alternatives. His choice in Step 5 may very likely be the same or similar to the alternative he placed at the top of his list at the end of Step 4.
Step 6: Take action:
This step involves taking some positive action based on the choices made in step 5 with respect to our case study this is the stage where Sam take action to buy the laptop that meet his requirement based on his own value system.
Step 7: Review your decision & its consequences
In this final step, consider the results of your decision and evaluate whether or not it has resolved the need you identified in Step 1. If the decision has not met the identified need, you may want to repeat certain steps of the process to make a new decision. For example, you might want to gather more detailed or somewhat different information or explore additional alternatives.
