Changing the default scale of a plot to a "custom scale"
You are almost there when you tried to set the xticks values.

Try 

ticks = [0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100]
plt.xticks(ticks, ticks)


The two parameters are the tick locations and the tick labels and they could be different, if you wanted.

Here's a full sample code

import matplotlib.pyplot as plt
import numpy as np
import pandas as pd
import random

point_min = 0 # low value for random data
point_max = 101 # high value for random data
point_count = 100 # number of data points

# generate a DataFrame
data3 = pd.DataFrame({'A':random.sample(range(point_min, point_max), point_count)
                    , 'B':random.sample(range(point_min, point_max), point_count)}
                    )

tick_freq = 10 # define how far apart you want your ticks

data3.plot(x='A', y='B', kind='scatter'
         , c=np.repeat(np.atleast_2d([.5, .6, .7]), data3.shape[0], axis=0) # marker color
         , figsize=(15, 5)) # wide plot to show all tick labels
plt.xticks(ticks, ticks)
plot;


The resulting graph looks as below