In theory you are correct — the US Aid to Israel was 2.5 Billion in 2009 -— 75% of which was subsidies to purchase or develop US weapons, so most of this money stays domestically in the USA and significantly decreases the “unit” costs of American weapons, as the USA buys these same weapons and the sales keep USA cost down.
It’s a significant help to Israel, still, to put the size of the aid in perspective, the USA gives Eqypt $1.7 billion and Jordan $.6 billion per year, $.6 billion to the “Palestinian authority” etc.
In short, the USA aid to Israel is about the same as the USA gives to terrorist nations.
Given Israel’s strategic role in the middle east, it is also money well spent. Certainly cheaper than an air-craft carrier fleet.
What have gotten for this "money well spent." Let's put emotion and religious arguments aside for a minute and be hard-headed realists here. U.S. aid to Israel has been the stated rationale for multiple attacks on our forces and has drawn us into two extremely expensive wars. One of the wars brought to power a symathizer with the Taliban, the other made Sadr into a kingmaker.
What have we gotten in exchange for this support which nobody can deny has pissed off every single country in an entire region? I suppose you could argue that Israel is a "reliable ally" but even that is not true. Reliable allies don't spy on each other. Israel, like most other countries, is motived by its own perceived national interest regardless of whether that national interest conflicts with our national interest.