When purchasing a Galileo-style refracting telescope the most important considerations are price and image quality. The Galileo refracting telescope consists of two lenses: a convex primary lens that curves outward and a concave eyepiece lens that curves inward. Large primary lenses greatly reduce chromatic aberration but are priced at a much higher rate than smaller lenses with poorer image quality.
Refracting telescopes suffer primarily from chromatic aberration, a phenomenon where color fringes or blurs at the edges of an object due to the lens refracting the various frequencies of light at different angles in the same manner that a prism divides white light into a rainbow. Telescopes are usually priced higher due to a larger aperture diameter to achieve sharper images and modifications to the lens to correct for chromatic aberration. However, when lens diameters are greater than 100mm, the Galileo-style telescope becomes prohibitively expensive with the body alone costing up to $700 as of 2015.
The original telescopes utilized by Galileo Galilei displayed in Florence's Museo Galileo were mostly composed of wood and metal and much less powerful, only able to magnify an image 30 times over. Exact replicas of Galileo's telescopes must be commissioned due to the non-standard measurements that Galileo utilized.