Reaching 1k quickly requires strategic. You need to focus on creating 3 types of content: trending sounds in your niche, educational "how-to" videos under 30 seconds and engaging duets with similar sized creators. Also, post consistently at optimal times (use TikTok Analytics if available) and engage authentically with 10-15 relevant comments per hour.
Many creators see success by studying their niche's top-performing content and adding unique value to those formats. Btw, if you want to invest in subscribers, you can opt for microjobs/minijobs (which are small paid tasks, no need for full time payment). They’re more affordable and customizable. Personally, I use the site SproutGigs and customize the number of daily subscribers I can gain per day + likes, comments, which makes it more organic and eventually reaches people interested in my niche. The ideal is to do it progressively, you can’t go from 0 to 1k, or your account will get banned.