I recommend buying off Ebay, as it is a great second-hand market and a Tamagotchi may run for around $30-45 (Canadian, with shipping). Weirdly enough, I have stumbled across Amazon selling an Angelgotchi, Mesutchi, and Osutchi new in package for around $30 (Canadian), but everything else is excessively over priced, except for the Tamagotchi Friends. A good rule of thumb is that Amazon sells new things but Ebay sell used things.
Right, there are allot of options but since you specified price, this narrows down the choices to the Vintage era, the Connection era, and Tamagotchi Friends. I'll give you a run down for each, and bear in mind that these are all English releases.
Vintage Era:
From my experience with the vintage era (Anglegotchi and P2), the versions offered are unique in their themes (themes often playing a big part in the gameplay) and have large pixels but have limited animations and games (usually just one only). They can be low maintenance once in adulthood, but they are programmed to get needier in old age and eventually die. Additionally, characters are limited but are often well known enough that they have a nostalgic appeal, as well as fitting nicely in their themes.
Connection Era:
Introduces allot more features and has a mix of new and old characters, but with a generally shorter life span due to evolving into the oldie characters. The early connections (V1-V3) have more characters from the vintage era, which works well in maintaining a nostalgic appeal but give a broader interaction. V1 doesn't have a shop while the V2 and V3 do. The later connections (V4, V4.5) have less vintage characters and the formula is a bit more regular due to the addition of stats, and also their is the job function which provides extra minigames.
V5, V5.5, and V6 break from the formula by allowing the user to raise three Tamagotchis at once and keep them permanently as their is no oldie stage. Once the tamagotchis become adults, they can activate the convenient dating channel function to marry. I've only experienced the V5, and I didn't like it that much because shop selection stays the same, you can only play games with one of the siblings, the minigames are limited (only 4), and raising three at once just seems to go through the characters awful fast. One big plus to the connection era is that, with the exception of the V.5-6, you can connect all versions together, as well as some of the Japanese ones too!
Tamagotchi Friends:
Basically, Tamagotchi Friends borrows elements from the newer, full-colour Tamagotchis and the Connection era. Most of the characters are modern but appear in grey-scale and similar to the V4 and V4.5, the formula is regular. The graphics are more detailed and there are a decent amount of games (more on the Dream Town version) but some do need to be unlocked, which can only be done with another Tamagotchi Friends. Items are replaced by jewelry, which only serves the purpose of being collected. Their are some cute alternate features to items that can be selected by the door icons options, but it depends on the version. The original Tamagotchi Friends has five minigames (two are locked) and an option to visit a park and see other Tamagotchis, while the Tamagotchi Friends Dream Town has eleven minigames (2 are locked) and has an option to visit a circus.
Recommendations:
1. V4 - Similar to the V4.5 but with a different character selection
2. V3 or V2 - Modern mechanics but blends character selection
3.Tamagotchi Friends Dream Town - Regular formula and modern characters
