diff --git a/source/scoring.py b/source/scoring.py
index e842dc8..74a3dad 100644
--- a/source/scoring.py
+++ b/source/scoring.py
@@ -6,6 +6,87 @@ __date__ = "02.05.2022"
 __version__ = "0.0.1"
 __license__ = "None"
 
-def eval_score(price, guessed_price):
-    return 0
+import pandas as pd
+import plotly.express as px
 
+
+def eval_score(price, guess):
+    """calculate the score of a user
+
+    Args:
+        price (float): price of the product
+        guess (float): guess of the user
+    
+    Returns:
+        float: score of the user
+
+    """
+    price = float(price)
+    guess = float(guess)
+
+    diff = abs(price - guess) # difference between price and guess in absolute value (e.g.: |-5| = 5)
+    rel = diff / price
+
+    if rel > 2: # guess extremely off -> 0 points
+        return 0
+
+    score = (1.0 - rel/2)*1000.0
+    score = round(score) # round to nearest integer
+
+    return score
+
+
+def get_relative_deviation(price, guess):
+    """calculate the relative deviation of a guess
+
+    Args:
+        price (float): price of the product
+        guess (float): guess of the user
+
+    Returns:
+        float: relative deviation of the guess (take times hundred for percentage)
+
+    """
+    price = float(price)
+    guess = float(guess)
+
+    diff = abs(price - guess) # difference between price and guess in absolute value (e.g.: |-5| = 5)
+    deviation = diff / price # formula for relative deviation: (price - guess) / price
+
+    return deviation
+
+
+def plot_linegraph(x_data, y_data):
+    """plot the score to test score function
+
+    Args:
+        x_data (list): list of prices
+        y_data (list): list of scores
+
+    Returns:
+        None
+
+    """
+    fig = px.line(x=x_data, y=y_data) # plot line graph from given data, only used for internal testing of score functions
+    fig.show()
+
+
+if __name__ == "__main__":
+    # run only directly for test reasons
+    # plotting might be deleted, only created for checking score function (it gives expected results)
+    PRICE = 2500
+    GUESS = 4900
+    print("This is a module with functions for evaluating scores of users. It is not intended to be run directly.")
+    print(eval_score(PRICE, GUESS))
+
+    scores = []
+    guesses = []
+    step = 2*round(PRICE/100)
+    for i in range(100):
+        guesses.append(i*step)
+        scores.append(eval_score(PRICE, PRICE-i*step))
+
+    print(scores)
+    print(guesses)
+
+    plot_linegraph(guesses, scores)