Any way to play against the Scandinavian Leonhardt Gambit?

I really like playing the Scandinavian, but it seems like after white goes for ... 4. b4, black is losing tempo or material in all lines. Is there any good way to equalize against the Leonhardt Gambit?

So, is that 1. e4 d5 2. exd5 Qxd5 3. Nc3 Qa5 4. b4? 

If so, what lines are worrying you? If not, what is the exact line that is causing you problems?

Ah yeah, I should have been more specific, sorry. I was referring mostly to this line:

After 6. Nb5, it feels like my queen's movement gets very restricted, while white's knight has a dominant position on the board. 6. Nb5 Qe4 just seems like it allows white easy development while continuing to hunt my queen, and 6. Qa5 runs into this:

I guess it's always bad to accept the gambit in this case? Maybe 3. Nc3 Qd6 is more solid for this reason? As a total chess beginner, any insight would be very helpful!

Well every move you make has a negative aspect to it. You weaken some squares, or lose control of squares or something like that. But more often than not when you make a move the positive aspect is stronger than the negative one.

However, if you start studying chess theory and opening principles you'll learn that you should not bring your queen out early in the opening because your opponent gets to develop pieces gaining a tempo on your queen. If you look at the best players in the world they don't play the scandinavian for a very specific reason. They'll play sometimes in blitz, maybe in rapid for fun or to try to get their opponents off guard, but they are GMs, they are allowed to break principles, and they do it in blitz and rapid, not classical when their opponents have plenty of time to think. 

Then again, scandinavian can be fun to play and if you're adamant on playing that and don't like facing the leonhardt gambit there are a few things you can do.  After 3.Nc3 You can move the queen to d6 or back to d8 instead of Qa5. Or try some cheesy traps by checking the whites king along the e file, but those are easy to refute so I wouldn't recommend, but sometimes people fall for it, especially low rated players in blitz.

Now if for some mysterious reason you really want to play ..3.Qa5 you must be open to the the very rare possibility of facing the leonhardt gambit. I for one love playing it as white since most people are not ready for it and will fall for traps, make bad moves, or waste some time thinking, besides losing tempos with the queen, not to mention taking them out of their opening prep. But as white, for my 5th move I don't play 5.Nb5,  I usually play 5.Rb8 attacking the queen and even 6.Rb5 if the queen goes back to a5 (which happens quite often... then you have to go Qa6 in the line of fire of my bishop and you'll lose another tempo). 

So if you see 5.Rb8 just know the best reply is ...5.Qd6

As white you'll often at the very least get your pawn back at some point with Rxb7 and even if you don't, it's blitz/rapid, people our level always make mistakes, especially with a queen out so early so a flank pawn does not make that much of a difference. Besides there's plenty of compensation, open b file for the rook, extra tempos, etc... .Not to mention the best part when you're playing some trigger-premove-happy-dude that is not expecting it and premoves Nf6, e6, c6 or whatever and hangs the queen on a5 on move 4 it's just too funny...

Now, after ..3.Qa5 and 4.b4 there are a few things you can do: one of them is not accepting the gambit.  But it's a bad  move to decline this gambit. Accepting it is the best move even though white does get some compensation as mentioned earlier. However,  I am pretty sure the best move after 5.Nb5 is  queen back to a5... then if 6.Bb2 push your c pawn to c6 kicking away the knight... c6 is a frequent theme on many lines of the scandinavian  controlling b5 and d5 squares and giving a useful, active and safe retreat square on c7 for your queen, allowing you to finish your development... and in this case kicking the knight away. 

In this line you mentioned it goes like this

1.e4 - d5

2.exd5 - Qxd5

3.Nc3 - Qa5

4.b4 - Qxb4

5.Nb5 - Qa5

6.Bb2 - c6

Whenever you're playing the scandinavian, even if it's not the leonhardt gambit, keep in mind this c6 move at some point, since it is a quite useful one that will often help you.

Hope this helps and good luck

I think this gambit should always be declined.

I play the Leonhardt a lot and my opponents usually move their queen to the center to avoid being trapped and develop the knights like this:

This usually leads to an exciting game.