攒钱 (zǎn qián) is the most common colloquial way to say 'save money' in northern China. It's more informal than 存钱 (cún qián), which sounds more like 'deposit money in the bank.'
The hand radical (left-side form of 手) signals a manual action — here gathering, scraping together and hoarding. It links 攒 with 拾, 抓 and 抠 in the family of acquisitive hand-actions, the daily verbs of getting and keeping.
Supplies the sound, drifting only in tone from zàn to zǎn. Visually 赞 contains two 夫 men plus a cowrie shell at the base — coincidentally a pile of money the saver hopes to amass — but its role here is purely phonetic.
