Just going to be honest because I want to help...
Three of those would give you an odd final ohm load, no matter how you wire them to a single amplifier. $70.00 X 3 = $210.00 for subs. Okay.
That amplifier... Honestly, for budget, i'd look into a more known and reputable company such as Maxxasonics products. (Hifonics, Crunch, MB Quart.) That amplifier is rated at 1100rms, but fused with 25 ampres, you would realistically see nothing more than 250 watts on perfect electrical at 2-ohms. Also, if that thing were to see a bit under 2-ohms, it would burn up real fast. Going back to your subwoofer decision, you would not be able to achieve a final 2-ohm load on three d2 voice coils. $80.00
Now my suggestions...
I have not put in hours of searching, but that is also something you can look into. Going off of what your original budget was: $290.00, I came up with this.
Subwoofers:
http://cgi.ebay.com/NEW-Hifonics-ZX1...t_2049w t_976
Two of these wired in parallel down to a 1-ohm final load. Rated 500rms a piece. (1000 total)
Amp:
http://cgi.ebay.com/Crunch-GPV2000-1...#ht_2009wt_976
I have owned one of these personally in the past, they will honestly do close to rated power on a solid electrical. Rated 1000rms at a 1-ohm load.
I have personally ran both of these pieces of equipment in the past. The subs are pretty beefy for what you will pay for them, and for ease, they sounded great sealed.
Both items sold by sonicelectronix ebay store.
Total cost: $300.00. Only $10.00 more than your original choices. And I am sure of these products, and sure you would be more satisfied as well.