What you posted is 常 (pinyin: chang2).
It means always or often, and with New Year decorations, can appear in combination for example in well-wishing phrases about happiness, fortunes, health, etc.
Recognition might be difficult because this is not the regular script typically seen in print text, but is instead written in semi-cursive script, also known as running script (pinyin: xing2 shu, t: 行書, s: 行书, Vietnamese: Hành thư)
- The bottom part of 常 is composed of 口 (mouth, pinyin: kou3) and 巾 (pinyin: jin), and normally these shapes are clearly discernible when looking at the regular script version
- but in your posted example it is condensed: the box-like 口 is reduced to a mere triangle and merged with the 巾
- the top half's strokes are still recognizable though, not drastically altered compared to regular script
- it shows condensed strokes typical of cursive script, yet has not been completely condensed, so it should be semi-cursive not cursive
Another example, listed as semi-cursive:
(source: supfree.net)
- notice the similar condensed shapes and strokes at the bottom
Source: http://shufa.supfree.net/raky.asp?zi=%B3%A3
As for the Simplified vs. Traditional aspect, not every Traditional Chinese character has been changed to make Simplified Chinese, for example: character for the number one 一 (pinyin: yi). 常 is also an example of a character that the authors of Simplified Chinese did not simplify, so under Simplified Chinese it remains unchanged from Traditional Chinese.
Hope this helped,
Happy Lunar New Year!
