uh, do the math... you're going to save thousands of dollars... a call to make sure the deal goes smooth is not going to break you.
The issue you need to understand is, when an American guy selling a US$2000 amp gets a message from Singapore, the first thing he thinks is "great - another scammer trying to rip me off."
The sad reality is, there's a lot of unscrupulous people in the world, and eBay, credit cards and paypal are tools they use. Calling is a wise idea. It helps the seller to understand you are genuinely interested. Believe me, you're going to find 5 amps you want to buy, and 4 of the sellers will say NO to you just because you live in Singapore. You may have to fax a copy of your IC, credit card, or maybe do an expensive bank draft if he doesn't believe in you.
What does a Boogie Mark V head cost from Bentley in KL? Over 14,000 MYR right? That's about SGD$5,800+ or US$4,110+
A Mark V head (new) in the USA is US$2000. (S$2800)
Shipping will cost you max $400 ~ (S$ 560)
Duty at ICA in Singapore will run you a few hundred ~ (S$ 400)
A step down transformer from Sim Lim, $100 (S$ 100)
total of $3,860max against S$5,800. You're gonna save $2k.
And you need to import the amp into Singapore and pay GST and transport costs on top of that $5,800. And what is Bentley going to do for after sale service for you? They're in another country!!! You're donating $2k to them for nothing.
The eBay protection also needs to be understood. For items above a certain value, the SELLER does not receive the funds immediately. The sale has to be completed (delivered and signed off by the buyer) so it could be months before the seller gets your money. Yeah, this appears to protect YOU the buyer, but guess what? This makes USA based sellers much LESS likely to want to do business with you.
I also want to tell you what else happens. You make awesome contacts. I don't want to name drop here, but I've now got direct access to some manufacturers and designers simply because I called and took the time to get to know them. Call at 6am when it is the afternoon in the USA. Best time to catch them. I've got free Tshirts, exclusive first-refusal offers, Autographed Overdrive pedal, immediate tech support, a replacement power supply fedex'd for free in 36 hours(!), and even invitations to go fishing with a top producer in Nashville - all from people I've never met, only talked to on the phone.
Make the call brother...