Many customers ask what is the highest power they can use with a telescope..Sadly some shops on line and high street etc do offer small telescopes with unrealistic magnifications of 500+. This will make the image totally unusable and make the unlucky buyer lose interest in astronomy very quickly.
For most small telescopes up to £100 I would recommend 2 or 3 eyepieces with powers in the 20x , 50x and 100x range. This will give a sensible choice of magnifications for a variety of uses from wide field star clusters to looking at the Moons around Saturn. Image shows the Skywatcher SWA Planetary eyepieces
Many (but not all) budget telescopes come with Kelner, Ramsdon, Modified achromatic eyepieces as standard. I would recommend upgrading to a set of plossls if budget allows.
Ostara plossl eyepieces can be purchased HERE from Northern Optics