New speaker for my new old Twingo

Hallö, I have been (almost) happy owner of an older Twingo since today. Unfortunately, I don’t have much money available to buy a few really good speakers and therefore I want to “transitional” speaker. I hope you can help me with this Wink. So I don’t know what kind of information you all need. It’s a Twingo with folding roof BJ 2000. On the internet it was offered as Twingo Matic Summer. Unfortunately, the Twingo has only 2 speakers in the dashboard and it is I would also like to replace this with a cheap radio… Since my reserves are used up, I want now for the next half year cheap loudspeakers. After that I would then upgrade bit by bit. In how far is it possible to install loudspeakers in the doors without sawing the whole door? A bass in the trunk or speaker in the hat rack is not possible for me. But now for the first time to the Übergan gslösung. Could you recommend me a cheap car radio (can also be used). For me it must have for half the year or vllt. also a little longer only CD. How about something like this: http://www.amazon.de/…/ref=pd_sim_ce_2. With the loudspeakers I know 0 unfortunately. With Amazon there are diverese mounts etc. I hope I have given all the relevant information and I hope you can help me. Many greetings, Daniel