I personally reccommend starting with the older tamagotchi. Like that of a P1 or a V1. Now if you cant e-bay one, sometimes I still see V3's in walmart or toystores,old stock.
if not try to get the lowest number there is. The V5's dont really have the FEEL of an actual tamagotchi,at least to me. (i own a P1,2 V1's several V3's a V4 a couple V4.5's and i gave my V5 to my sister >.> ) but then again,V5's also can connect with older versions,which is a major problem in my eyes. I can understand the jap ones not being able to communicate with american ones...but still...V5's are american.
but that's just my point of veiw. try for an older one to get a better pet-caretaking experience. =)
Edit: Welcome to TT! If you want,we can be buddies!
You can research. mimitchi.com is a great source of information for tamagotchis. tamenagerie.com contains information on evey tama released. pixelmood.com is a good source of information as well. and then there is our very own tamatalk! when i want to buy a tama i always read other peoples logs, find out how popular the version is and check out the sites above. you can also google pictures.
i think u should not buy the v5 trust me the v5 gets boring and a lot of people agree with me so i say like maybe get a v1-v4.5 those i think r the best tamas
i think i will buy a v3 or v4.5(if i find any!! tamagotchi is very hard to find here.)
i looked at a lot of sites,images and topics at TT and saw that v5 isnt really great(i didnt really like the family idea ).so i think a v4.5 is good for start