This will very much depend on the jurisdiction (country). It will also depend on how much you quote or reproduce from a gioven site, compartesd to the size of the original site.
You are correct that a single number, such as a target price, cannot be protected by copyright, and you may copy it. Attribution is, in my view, ethically required whether it is legally mandated or not.
As to quotign from a description text, in the US this might be held to be fair use. What is ir is not fair use. See Is this copyright infringement? Is it fair use? What if I don't make any money off it? and Does Fair Use of copyright apply to educational youtube channels? for more detail. See also the tag search that lists many question threads on fair use.
Here the use made does not seem trasformatice -- you would be using the description ext for muvh the same purpose as the originals, and it is aleast possible that your site could prove to function as a substitute for the original sites. Those factors would =weigh against a fair use finding, but a full analysis would require detail not included in teh qustuioin, adn might come to different results for different sources.
In the UK and several other countries, there is an exception to copyright known as *fair dealing. That is usually somewhat narrower than fair use. In other countries there are various exceptions to copyright. These vary widely.
You might be well advised to take the ideas from the published descriptions, and reword them significantly. This will reduce the chance of a valid claim from the owner of the source site.