I don't know how much swarm there is for sale (since I can't really understand the market's order book at counterparty.co), but I've purchased half of my swarm at more than 7000swarm per BTC from counterparty.co.. which is about ~30% cheaper than buying directly from swarmcorp.com.
a9e13 a day ago 0.00225225 XCP/SWARMPRE 888 XCP 100% 20,000 SWARMPRE 100% In 725 blocks
80751 about 24 hours ago 0.0022 XCP/SWARMPRE 495.55555556 XCP 99% 11,199.55555566 SWARMPRE 99% In 805 blocks
12801 about 7 hours ago 22.50541437 XCP/SWARMPRE 22.2574 XCP 100% 500.9120098 SWARMPRE 100% In 923 blocks
cc046 about 15 hours ago 0.0803133 BTC/SWARMPRE 0.10755616 BTC 100% 0.00863819 SWARMPRE 100% In 882 blocks 0.00107558 BTC 100%
b6806 7 days ago 0.6 BTC/SWARMPRE 3.3125 BTC 95% 20,111.60714286 SWARMPRE 95% In 1861 blocks 0.001 BTC
Price display is wrong in counterwallet, wtf, it's actually 22,5225 SWARMPRE/XCP and not 0.00225225 XCP/SWARMPRE
in XCP : approx 31200 SWARMPRE for 1383 XCP, or 5.532 BTC at 0.004 XCP/BTC rate = 5639,91 SWARMPRE/BTC (in XCP)
in BTC : 20111 SWARMPRE for 3.3125 = 6071 SWARMPRE/BTC
Last time I've checked, crowdsale rate was around 5140 SWARMPRE/BTC
Also note that if you purchase via the crwodsale, you are "diluting" the future SWARM to be distributed (you'll get more SWARM/SWARMPRE if you purchase via counterwallet)