I'm grinding a bankroll from $12, currently at ~$100 and my trial for HEM2 is coming to an end.

I don't really want to spend 60% of my roll on a micro version of HEM.

Is it worth doing one of the promotions like playing on 888poker? My understanding is that all I need to do is rake $35 AND i get a 100% deposit bonus and once I've raked $35 I get $100 of HEM vouchers?

Am I correct in thinking this?? This is insane value especially with the deposit bonus. I'm pretty sure I don't even need to be a winning player to profit here?

http://www.holdemmanager.com/store/poker-sites.php

Step 1) Download 888 Poker through this link. (Russian customers, use this LINK or download it directly from this LINK. Greek customers, use this LINK)

Step 2) Deposit at least $30.00, 888 Poker will add a 100% sign up bonus up to $400.00!

Step 3) Let us know your 888 Poker username by clicking "Next" at the bottom of the page.

Step 4) Begin playing, rake $35.

The "catch" is that at the micros it's gonna take a lot of hands to add up to $35 of rake. You can check your current HEM stats to see how much you've paid to get an idea of how long it will take to clear.

ATM I've raked $25 on stars playing $1.50 HUSnGs in a week with a 63% winrate. I feel like if I put some serious hours in I can get HEM for free within a week and I only need to breakeven for this to be worthwhile.

There's no real catch, AFAIK. This is how I got my copy of HEM for free. It was a few years ago, and I played on Stars when PASG/HEM had an affiliate deal with them, so the value of the deal will be different today (and will likely vary from site to site). It took me ages to pay the rake (I was playing 2NL and I was losing for about half the hands I grinded, as I was in too much of a hurry, so played too many tables), but I think it was a a decent freebie, as I was learning the game and wasn't sure if I could justify paying for the program if it turned out that poker got boring really quickly.

Signing up with an alternative affiliate and getting rakeback in the longterm might be worth a lot more money to you though. (e.g. some training sites might give you free access to videos worth a lot more than $100+, or you might be able to enrol in rake races that will be worth $100+ per month if you end up playing higher stakes.)
If you're considering signing up with 888 anyway, have a look at sites like PokerVIP or rakeback.com to see if their 888 offers sound better for you.
Note also that traffic will be lower on other sites to Stars, so you might not be able to churn through the rake target on 888 as quickly as you hope/expect. If you're planning on sticking with poker for a while, you'll buy the HUD eventually anyway, and it will pay for itself many times over. (Assuming HUDs don't get banned).
In some ways, getting a long-term rakeback deal is much more important than getting something nice "instantly" and then nothing again. e.g. Who wants a HUD, or a t-shirt and a mousemat worth $30 if a rakeback affiliate can offer you 1.5bb/100 for the rest of your entire career?