BIs' needed depends on skill level.
Worth starting at $1.50 level to get a feel of them
Your last chips are so much more valuable in these. If I remember correctly its $1.35 for finishing in top 5 plus $0.04 for every 100 chips. If you have 1000 chips you get $1.75 175/1000 =0.175. Each chip is worth 0.175. If you have 10000 chips (very unlikely but means I don't have to get my calculator) you geet $5.35 535/10000 = 0.0535. 0.175/0.0535 = just over 3 (about 3.3 I think). So as a shortstack each chip you have is 3 times as valuable as when you are a big stack. Use this knowledge to abuse the bubble and make lightish calls from BB when you think you have odds
(when you are bigstack though, not shortstacked).
Also don't play too tight so you end up low stacked alot as you need to have some FE on the bubble to make steals.